WorldWideScience

Sample records for gaseous atmospheres inflammabilite

  1. Magnesium and uranium ignition in different gaseous atmospheres; Inflammabilite du magnesium et de l'uranium dans l'air et le gaz carbonique

    Energy Technology Data Exchange (ETDEWEB)

    Darras, R; Baque, P; Leclercq, D [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    Magnesium, uranium and some of their alloys burning temperatures have been systematically determined in an air or carbon dioxide atmosphere, either dry or wet. Two different ways of heating have been used: either continuously rising up the temperature, or heating to and then maintaining a constant temperature. The results are clearly different in the two cases. Besides, if moisture has little effect on the magnesium burning temperatures in air, it does lower them by about 130-140 deg. C in CO{sub 2}. The differences of sight between the burning of magnesium and uranium have been noticed; this leads to distinguish between an 'ignition' and an 'inflammation'. (author) [French] Les temperatures auxquelles apparait la combustion vive du magnesium, de l'uranium et certains de leurs alliages ont ete determinees systematiquement dans l'air et le gaz carbonique, soit secs, soit humidifies. On a mis en evidence l'influence du mode de chauffage sur les resultats: soit montee en temperature continue, soit stabilisation a partir d'une certaine temperature. En outre, si la presence d'humidite affecte peu les temperatures de combustion vive du magnesium dans l'air, elle les abaisse de 130 a 140 deg. C dans le gaz carbonique. Les differences d'aspect entre la combustion vive du magnesium et de l'uranium ont egalement ete remarquees, ce qui amene notamment a distinguer une 'ignition' d'une 'inflammation'. (auteur)

  2. Frost formation under different gaseous atmospheres

    International Nuclear Information System (INIS)

    Fukada, Satoshi; Tsuru, Hisanori; Nishikawa, Masabumi

    1995-01-01

    Rates of water frost growth in a vessel with a cooled horizontal plate were experimentally determined under reduced pressure atmospheres of hydrogen, helium, methane and nitrogen. The mass deposited on the cooled surface under each of the atmospheres was almost in proportion to time. The Sherwood number under the condition of no mist formation, Sh 0 , in the atmospheres of methane and nitrogen was in good agreement with Catton's equation for natural convection between horizontal parallel plates. Sh 0 in a hydrogen atmosphere was unity, which corresponds to control by molecular diffusion in the stagnant gas. The tendency of the decrease in Sh due to mist formation could be evaluated well by multiplying Sh 0 by a factor ζ CSM . The ζ CSM value was calculated based on the critical supersaturation model as a function of the two interface temperatures and the total pressure. Frost growth rates under each atmosphere were in proportion to [(T S1 -T W1 )t/(1+1/A S1 )] 0.5 . The proportional constant for hydrogen was greater than that for any other tested gas. Agreement and disagreement of the frost effective thermal conductivity with previous models were discussed. (author)

  3. Relationship between epiphytic lichens, trace elements and gaseous atmospheric pollutants

    NARCIS (Netherlands)

    Dobben, van H.F.; Wamelink, G.W.W.; Braak, ter C.J.F.

    2001-01-01

    A study was conducted to determine the joint effect of gaseous atmospheric pollutants and trace elements on epiphytic lichens. We used our data to test the hypothesis that lichens are generally insensitive to toxic effects of trace elements, and can therefore be used as accumulator organisms to

  4. Chapter 4 Gaseous Elemental Mercury in the Ambient Atmosphere

    DEFF Research Database (Denmark)

    Ariya, Parisa A.; Skov, Henrik; Grage, Mette M L

    2008-01-01

    Understanding the kinetics and mechanisms associated with the atmospheric chemistry of mercury is of great importance to protecting the environment. This review will focus on theoretical calculations to advance understanding of gas phase oxidation of gaseous elemental mercury (GEM) by halogen spe...

  5. Atmospheric Gaseous Plasma with Large Dimensions

    Science.gov (United States)

    Korenev, Sergey

    2012-10-01

    The forming of atmospheric plasma with large dimensions using electrical discharge typically uses the Dielectric Barrier Discharge (DBD). The study of atmospheric DBD was shown some problems related to homogeneous volume plasma. The volume of this plasma determines by cross section and gas gap between electrode and dielectric. The using of electron beam for volume ionization of air molecules by CW relativistic electron beams was shown the high efficiency of this process [1, 2]. The main advantage of this approach consists in the ionization of gas molecules by electrons in longitudinal direction determines by their kinetic energy. A novel method for forming of atmospheric homogeneous plasma with large volume dimensions using ionization of gas molecules by pulsed non-relativistic electron beams is presented in the paper. The results of computer modeling for delivered doses of electron beams in gases and ionization are discussed. The structure of experimental bench with plasma diagnostics is considered. The preliminary results of forming atmospheric plasma with ionization gas molecules by pulsed nanosecond non-relativistic electron beam are given. The analysis of potential applications for atmospheric volume plasma is presented. Reference: [1] S. Korenev. ``The ionization of air by scanning relativistic high power CW electron beam,'' 2002 IEEE International Conference on Plasma Science. May 2002, Alberta, Canada. [2] S. Korenev, I. Korenev. ``The propagation of high power CW scanning electron beam in air.'' BEAMS 2002: 14th International Conference on High-Power Particle Beams, Albuquerque, New Mexico (USA), June 2002, AIP Conference Proceedings Vol. 650(1), pp. 373-376. December 17.

  6. Natural sources of gaseous pollutants in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Altshuller, A P

    1958-01-01

    Various gaseous pollutants including ozone, nitrous oxide, nitric oxide, nitrogen dioxide, methane, hydrogen, formaldehyde, ammonia, hydrogen sulfide, mercaptans, chlorine compounds and free radicals can be formed by natural processes such as ultraviolet photochemical processes in the upper atmosphere and microbiological processes. The modes of formation and destruction of these gases, especially of their concentrations in the atmosphere, and the various reactions in which these gases can participate with each other are discussed in detail. 114 references.

  7. Influence of a gaseous atmosphere on fatigue crack propagation

    International Nuclear Information System (INIS)

    Henaff, G.

    2002-01-01

    The paper presents a review of the current knowledge on the influence of gaseous atmospheres, and primarily ambient air, on fatigue crack propagation in metallic alloys. Experimental evidence of the effect of exposure to ambient air or any moist environment on fatigue crack propagation in steels is first proposed. The different interacting processes are analyzed so as to clearly uncouple the influence of the various factors on crack growth resistance. Two distinct mechanisms are identified: the adsorption of vapour molecules and hydrogen assisted fracture at crack tip. (author)

  8. Uranium/water vapor reactions in gaseous atmospheres

    International Nuclear Information System (INIS)

    Jackson, R.L.; Condon, J.B.; Steckel, L.M.

    1977-07-01

    Experiments have been performed to determine the effect of varying humidities, gaseous atmospheres, and temperatures on the uranium/water vapor reaction. A balance, which allowed continuous in-system weighings, was used to determine the rates of the uranium/water vapor reactions at water vapor pressures of 383, 1586, and 2853 Pa and at temperatures of 80, 100, and 150 0 C in atmospheres of hydrogen, argon, or argon/oxygen mixtures. Based on rate data, the reactions were characterized as hydriding or nonhydriding. Hydriding reactions were found to be preferred in moist hydrogen systems at the higher temperatures and the lower humidities. The presence of hydrogen in hydriding systems was found to initially inhibit the reaction, but causes an acceleration of the rate in the final stages. In general, reaction rates of hydriding systems approached the hydriding rates calculated and observed in dry hydrogen. Hydriding and nonhydriding reaction rates showed a positive correlation to temperature and water vapor pressure. Final reaction rates in moist argon/oxygen mixtures of 1.93, 4.57, and 9.08 mole percent oxygen were greater than the rates observed in moist hydrogen or argon. Final reaction rates were negatively correlated to the oxygen concentration

  9. Presentation and interpretation of field experiments of gaseous UF6 releases in the atmosphere

    International Nuclear Information System (INIS)

    Crabol, B.; Boulaud, D.; Deville-Cavelin, G.

    1992-01-01

    An experimental programme concerning the behaviour of UF 6 released in gaseous phase in the atmosphere has been conducted in the years 1986-1989 by the french Atomic Energy Commission and Eurodif. Three field tests have been performed on the CEA/CESTA experimental site. These experiments permitted to get informations about the kinetics of the hydrolysis reaction of the UF 6 , the behaviour of the hydrolysis products in the atmosphere and the granulometry of the solid particles

  10. Study of the high power laser-metal interactions in the gaseous atmospheres

    Science.gov (United States)

    Lugomer, Stjepan; Bitelli, G.; Stipancic, M.; Jovic, F.

    1994-08-01

    The tantalum and titanium plates were treated by pulsed, high power CO2 laser in the pressurized atmospheres of N2 and O2. Studies performed by the optical microscopy, microhardness measurements, and the auger electron spectroscopy revealed: (1) topographic modification of the surface caused by the temperature field; (2) metal hardening, caused by the laser shock; and (3) alloying/cladding, caused by the chemical reaction between the metal surface and the gaseous atmosphere.

  11. Presentation and interpretation of field experiments of gaseous UF6 releases in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Crabol, B.; Boulaud, D.; Deville-Cavelin, G. [CEA Centre d`Etudes de Fontenay-aux-Roses, 92 (France). Dept. de Protection de l`Environnement et des Installations; Geisse, C.; Iacona, L. [EURODIF, 26 - Pierrelatte (France)

    1992-12-31

    An experimental programme concerning the behaviour of UF{sub 6} released in gaseous phase in the atmosphere has been conducted in the years 1986-1989 by the french Atomic Energy Commission and Eurodif. Three field tests have been performed on the CEA/CESTA experimental site. These experiments permitted to get informations about the kinetics of the hydrolysis reaction of the UF{sub 6}, the behaviour of the hydrolysis products in the atmosphere and the granulometry of the solid particles.

  12. Magnesium and uranium ignition in different gaseous atmospheres

    International Nuclear Information System (INIS)

    Darras, R.; Baque, P.; Leclercq, D.

    1960-01-01

    Magnesium, uranium and some of their alloys burning temperatures have been systematically determined in an air or carbon dioxide atmosphere, either dry or wet. Two different ways of heating have been used: either continuously rising up the temperature, or heating to and then maintaining a constant temperature. The results are clearly different in the two cases. Besides, if moisture has little effect on the magnesium burning temperatures in air, it does lower them by about 130-140 deg. C in CO 2 . The differences of sight between the burning of magnesium and uranium have been noticed; this leads to distinguish between an 'ignition' and an 'inflammation'. (author) [fr

  13. Estimation of radionuclide releases in atmosphere from Cernavoda NPP based on continuous gaseous effluent monitoring

    International Nuclear Information System (INIS)

    Bobric, E.; Murgoci, S.; Popescu, I.; Ibadula, R.

    2001-01-01

    Monitoring of gaseous effluents from Cernavoda NPP is performed to assess the environmental impact of the plant operation. The results of the monitoring program are used to evaluate the population doses in order to ensure that the emissions of radionuclides in air are below regulatory limits and radiation doses are maintained ALARA. It complements, but is independent from the Operational Environmental Monitoring Program for Cernavoda NPP. Gaseous effluent monitors provide continuous indication of the radioactivity content in atmospheric emissions. Except for noble gases, these monitors also collect samples for later detailed analysis in the station Health Physics Laboratory. This paper presents the main equipment and the results of the gaseous effluents monitoring program in order to assess the impact of Cernavoda NPP operation and to predict the future releases as function of radionuclides concentrations in CANDU systems, based on the identified trends.(author)

  14. Measurement of viscosity of gaseous mixtures at atmospheric pressure

    Science.gov (United States)

    Singh, J. J.; Mall, G. H.; Chegini, H.

    1986-01-01

    Coefficients of viscosity of various types of gas mixtures, including simulated natural-gas samples, have been measured at atmospheric pressure and room temperature using a modified capillary tube method. Pressure drops across the straight capillary tube section of a thermal mass flowmeter were measured for small, well-defined, volume flow rates for the test gases and for standard air. In this configuration, the flowmeter provides the volumetric flow rates as well as a well-characterized capillary section for differential pressure measurements across it. The coefficients of viscosity of the test gases were calculated using the reported value of 185.6 micro P for the viscosity of air. The coefficients of viscosity for the test mixtures were also calculated using Wilke's approximation of the Chapman-Enskog (C-E) theory. The experimental and calculated values for binary mixtures are in agreement within the reported accuracy of Wilke's approximation of the C-E theory. However, the agreement for multicomponent mixtures is less satisfactory, possible because of the limitations of Wilkes's approximation of the classical dilute-gas state model.

  15. Hydrogen Bonding Interaction between Atmospheric Gaseous Amides and Methanol

    Directory of Open Access Journals (Sweden)

    Hailiang Zhao

    2016-12-01

    Full Text Available Amides are important atmospheric organic–nitrogen compounds. Hydrogen bonded complexes of methanol (MeOH with amides (formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide and N,N-dimethylacetamide have been investigated. The carbonyl oxygen of the amides behaves as a hydrogen bond acceptor and the NH group of the amides acts as a hydrogen bond donor. The dominant hydrogen bonding interaction occurs between the carbonyl oxygen and the OH group of methanol as well as the interaction between the NH group of amides and the oxygen of methanol. However, the hydrogen bonds between the CH group and the carbonyl oxygen or the oxygen of methanol are also important for the overall stability of the complexes. Comparable red shifts of the C=O, NH- and OH-stretching transitions were found in these MeOH–amide complexes with considerable intensity enhancement. Topological analysis shows that the electron density at the bond critical points of the complexes fall in the range of hydrogen bonding criteria, and the Laplacian of charge density of the O–H∙∙∙O hydrogen bond slightly exceeds the upper value of the Laplacian criteria. The energy decomposition analysis further suggests that the hydrogen bonding interaction energies can be mainly attributed to the electrostatic, exchange and dispersion components.

  16. Hydrogen Bonding Interaction between Atmospheric Gaseous Amides and Methanol.

    Science.gov (United States)

    Zhao, Hailiang; Tang, Shanshan; Xu, Xiang; Du, Lin

    2016-12-30

    Amides are important atmospheric organic-nitrogen compounds. Hydrogen bonded complexes of methanol (MeOH) with amides (formamide, N -methylformamide, N , N -dimethylformamide, acetamide, N -methylacetamide and N , N -dimethylacetamide) have been investigated. The carbonyl oxygen of the amides behaves as a hydrogen bond acceptor and the NH group of the amides acts as a hydrogen bond donor. The dominant hydrogen bonding interaction occurs between the carbonyl oxygen and the OH group of methanol as well as the interaction between the NH group of amides and the oxygen of methanol. However, the hydrogen bonds between the CH group and the carbonyl oxygen or the oxygen of methanol are also important for the overall stability of the complexes. Comparable red shifts of the C=O, NH- and OH-stretching transitions were found in these MeOH-amide complexes with considerable intensity enhancement. Topological analysis shows that the electron density at the bond critical points of the complexes fall in the range of hydrogen bonding criteria, and the Laplacian of charge density of the O-H∙∙∙O hydrogen bond slightly exceeds the upper value of the Laplacian criteria. The energy decomposition analysis further suggests that the hydrogen bonding interaction energies can be mainly attributed to the electrostatic, exchange and dispersion components.

  17. Calculations of color and visibility in urban atmospheres polluted by gaseous NO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Hodkinson, J.R.

    1966-01-01

    Calculations are made of the optical effects of persistent gaseous NO/sub 2/ pollution at 0.2-2 ppm in a city atmosphere in both the presence and absence of a polluting aerosol which does not absorb light or NO/sub 2/. It is concluded that the coloring of the horizon sky and of distant white objects would resemble whiskey, tea or cola-drinks, and the visual range would be markedly reduced. 2 references, 3 figures, 1 table.

  18. Presentation and interpretation of field experiments of gaseous UF{sub 6} releases in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Crabol, B.; Boulaud, D.; Deville-Cavelin, G. [CEA/Inst. de Protection et de Surete Nucleaire, Dept. de Protection de l' Environnement et des Installations, Fontenay-aux-Roses (France); Geisse, C.; Iacona, L. [EURODIF/Production, Site de Tricastin, Pierrelatte Cedex (France)

    1992-07-01

    An experimental programme concerning the behaviour of UF{sub 6} released in gaseous phase in the atmosphere has been conducted in the years 1986-1989 by the French Atomic Energy Commission and EURODIF. Three field tests have been performed on the CEA/CESTA experimental site. These experiments permitted to get information about the kinetics of the hydrolysis reaction of the UF{sub 6}, the behaviour of the hydrolysis products in the atmosphere and the granulometry of the solid particles. (author)

  19. Study on the surface oxidation of uranium in different gaseous atmospheres

    International Nuclear Information System (INIS)

    Wang Xiaoling; Fu Yibei; Xie Renshou

    1996-03-01

    The studying for the surface oxidation of uranium and oxide by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), and the surface oxidation of uranium in different gaseous atmospheres such as O 2 , H 2 , CO, CO 2 , H 2 O(v) and air were reviewed. The surface oxidation of uranium is greatly influenced by a number of parameters including atmospheric temperature, pressure, diffusion of adsorbed gas atoms through the oxide layer, surface and interface chemical component, and defect structure and electron nature of the oxide layer. The initial oxidation mechanism and kinetics have been discussed. Suggestions for future work have also been presented. (32 refs., 7 figs., 5 tabs.)

  20. High-power laser-metal interactions in pressurized gaseous atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Bitelli, G. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione; Lugomer, S.; Furic, K.; Ivanda, M. [Ruder Boskovic Institute, Zagreb (Croatia); Stipancic, M. [Electrotechnical faculty, Osijek (Croatia); Stubicar, M. [Faculty of natural sciences and mathematics, Zagreb (Croatia); Gamulin, O. [School of medicine, Univ. of Zagreb, Zagreb (Croatia)

    1996-09-01

    Metal surfaces were irradiated in pressurized gaseous atmospheres by a CO{sub 2} laser beam. The gaseous pressures ranged from 2 atm to 6 atm, the energy density of the light beam was about 20-50 J/cm{sup 2} with a power density {approx} 10{sup 9} W/cm{sup 2} and a pulse duration p 150 ns. In the above conditions some new effects were observed. The laser-material interaction occurred in a highly absorptive plasma regime, meaning that the metal surface was effectively screened from the beam. The interaction ended either with plasma adiabatic expansion, in the case of Mo (in O{sub 2}), Te (in N{sub 2}) and T{sub i} (in N{sub 2}), or with plasma explosion, in the case of T{sub i} (in O{sub 2}). The metal surface properties were studied by means of optical analysis, microhardness tests, X-ray diffraction and Raman backscattering.

  1. New Constraints on Terrestrial Surface-Atmosphere Fluxes of Gaseous Elemental Mercury Using a Global Database.

    Science.gov (United States)

    Agnan, Yannick; Le Dantec, Théo; Moore, Christopher W; Edwards, Grant C; Obrist, Daniel

    2016-01-19

    Despite 30 years of study, gaseous elemental mercury (Hg(0)) exchange magnitude and controls between terrestrial surfaces and the atmosphere still remain uncertain. We compiled data from 132 studies, including 1290 reported fluxes from more than 200,000 individual measurements, into a database to statistically examine flux magnitudes and controls. We found that fluxes were unevenly distributed, both spatially and temporally, with strong biases toward Hg-enriched sites, daytime and summertime measurements. Fluxes at Hg-enriched sites were positively correlated with substrate concentrations, but this was absent at background sites. Median fluxes over litter- and snow-covered soils were lower than over bare soils, and chamber measurements showed higher emission compared to micrometeorological measurements. Due to low spatial extent, estimated emissions from Hg-enriched areas (217 Mg·a(-1)) were lower than previous estimates. Globally, areas with enhanced atmospheric Hg(0) levels (particularly East Asia) showed an emerging importance of Hg(0) emissions accounting for half of the total global emissions estimated at 607 Mg·a(-1), although with a large uncertainty range (-513 to 1353 Mg·a(-1) [range of 37.5th and 62.5th percentiles]). The largest uncertainties in Hg(0) fluxes stem from forests (-513 to 1353 Mg·a(-1) [range of 37.5th and 62.5th percentiles]), largely driven by a shortage of whole-ecosystem fluxes and uncertain contributions of leaf-atmosphere exchanges, questioning to what degree ecosystems are net sinks or sources of atmospheric Hg(0).

  2. Transfer of gaseous iodine (I2) from atmosphere to rice grains through dry deposition

    International Nuclear Information System (INIS)

    Uchida, Shigeo; Muramatsu, Yasuyuki; Sumiya, Misako; Ohmomo, Yoichiro

    1989-01-01

    The report briefly outlines parameters required to determine the transfer of 129 I from the atmosphere to rice grains, and presents results of a study in which the transfer of iodine from the atmosphere to rice grains is calculated using empirically determined parameters. There are four major parameters required for the calculation: (1) the major transfer route (translocation either from leaves or from the surface of hulls to rice grains), (2) rate of deposition onto the surface of leaves or hulls, (3) biological half-life of iodine deposited on leaves or hulls, and (4) either the rate of translocation from leaves to hulls (where the translocation from leaves is the major route) or the ratio of iodine distribution among hulls, unpolished rice grains, and polished rice grains (where the translocation from hulls is the major route). Techniques available to determine the translocation route, deposition rate, biological half-life and distribution ratio are outlined. Chemical forms of iodine, parameters relating to the transfer of gaseous iodine to paddy rice, and calculation models are also described. (N,K.)

  3. Method and device to measure the concentration of the various isotopes of radon in a gaseous atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Guelin, M; LeGac, J; Caruau, J

    1990-11-30

    Device to implement the method according to claim 1, wherein it is constituted of a vessel provided with an intake tube and an evacuation tube for the gaseous atmosphere and whose inside forms the closed sampling space, is subdivided into a large number of small elementary intercommunicating volumes so as to enable the taken gaseous sample to be homogenized, as well as to allow for the diffusion and the spatially homogeneous trapping of all the solid daughter products thus constituting a homogeneous emitting source for the spectrometry chain which examines this source from outside. (author). 4 figs.

  4. Depletion of atmospheric gaseous elemental mercury by plant uptake at Mt. Changbai, Northeast China

    Directory of Open Access Journals (Sweden)

    X. Fu

    2016-10-01

    Full Text Available There exists observational evidence that gaseous elemental mercury (GEM can be readily removed from the atmosphere via chemical oxidation followed by deposition in the polar and sub-polar regions, free troposphere, lower stratosphere, and marine boundary layer under specific environmental conditions. Here we report GEM depletions in a temperate mixed forest at Mt. Changbai, Northeast China. The strong depletions occurred predominantly at night during the leaf-growing season and in the absence of gaseous oxidized mercury (GOM enrichment (GOM  <  3 pg m−3. Vertical gradients of decreasing GEM concentrations from layers above to under forest canopy suggest in situ loss of GEM to forest canopy at Mt. Changbai. Foliar GEM flux measurements showed that the foliage of two predominant tree species is a net sink of GEM at night, with a mean flux of −1.8 ± 0.3 ng m2 h−1 over Fraxinus mandshurica (deciduous tree species and −0.1 ± 0.2 ng m2 h−1 over Pinus Koraiensis (evergreen tree species. Daily integrated GEM δ202Hg, Δ199Hg, and Δ200Hg at Mt. Changbai during 8–18 July 2013 ranged from −0.34 to 0.91 ‰, from −0.11 to −0.04 ‰ and from −0.06 to 0.01 ‰, respectively. A large positive shift in GEM δ202Hg occurred during the strong GEM depletion events, whereas Δ199Hg and Δ200Hg remained essentially unchanged. The observational findings and box model results show that uptake of GEM by forest canopy plays a predominant role in the GEM depletion at Mt. Changbai forest. Such depletion events of GEM are likely to be a widespread phenomenon, suggesting that the forest ecosystem represents one of the largest sinks ( ∼ 1930 Mg of atmospheric Hg on a global scale.

  5. Graphic displays on PCs of gaseous diffusion models of radionuclide releases to the atmosphere

    International Nuclear Information System (INIS)

    Campo Ortega, E. del

    1993-01-01

    The well-known MESOI program has been modified and improved to adapt it to a PC/AT with VGA colour monitor. Far from losing any of its powerful characteristics to calculate the transport, diffusion, deposition and decay of gaseous radioactive effluents discharged to the atmosphere, it has been enhanced to allow graphic viewing of concentrations, wind speed and direction and puff locations in colour, all on a background map of the site. The background covers a 75 x 75 km square and has a graphic grid density of 421 x 421 pixels. This means that effluent concentration is represented approximately every 170 metres in the 'clouded-area'. Among the modifications and enhancements made, the following are of particular interest: 1. A new subroutine called NUBE has been added, which calculates the distribution of effluent concentration of activity in a grid of 421 x 421 pixels. 2. Several subroutines have been added to obtain graphic displays and printouts of the cloud, wind field and puff locations. 3. Graphic display of the geographic plane of the area surrounding the effluent release point. 4. Off-line preparation of meteorological and topographical data files necessary for program execution. (author)

  6. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, G. [Laboratoire d' Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d' Assise, 10, rue de l' Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l' environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l' Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

    2012-10-15

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  7. The effect of surface treatment and gaseous rust protection paper on the atmospheric corrosion stability of aluminium alloy

    International Nuclear Information System (INIS)

    Gao Guizhong

    1992-03-01

    The experimental results of atmospheric corrosion of 166 aluminium alloy of Al-Mg-Si-Cu system and 167 aluminium alloy of Al-Mg-Si-Cu-Fe-Ni system for different surface treatment and different wrapping papers used are introduced. The results show: 1. The composition of aluminium alloy has some effect on the performance of atmospheric corrosion stability and the local corrosion depth for 167 aluminium alloy specimen is considerable. 2. After 8 years storage, the 167 aluminium alloy tubular specimen, which was treated with surface treatment in deionized water at 100 ∼ 230 C degree, has no spot of atmospheric corrosion found. 3. Within the test period, the performance of atmospheric corrosion stability by sulphuric-acid anodization film is remarkable. 4. The No. 19 gaseous rust protection paper has no effect of atmospheric corrosion stability on the 166 and 167 aluminium alloys which were treated with quenching and natural ageing method

  8. Adaption and use of a quadcopter for targeted sampling of gaseous mercury in the atmosphere.

    Science.gov (United States)

    Black, Oscar; Chen, Jingjing; Scircle, Austin; Zhou, Ying; Cizdziel, James V

    2018-03-22

    We modified a popular and inexpensive quadcopter to collect gaseous mercury (Hg) on gold-coated quartz cartridges, and analyzed the traps using cold vapor atomic fluorescence spectrometry. Flight times averaged 16 min, limited by battery life, and yielded > 5 pg of Hg, well above the limit of detection (quadcopter, we measured atmospheric Hg near anthropogenic emission sources in the mid-south USA, including a municipal landfill, coal-fired power plant (CFPP), and a petroleum refinery. Average concentrations (± standard deviation) immediately downwind of the landfill were higher at ground level and 30 m compared to 60 and 120 m (5.3 ± 0.5 ng m -3 , 5.4 ± 0.7 ng m -3 , 4.2 ± 0.7 ng m -3 , and 2.5 ± 0.3 ng m -3 , respectively). Concentrations were also higher at an urban/industrial area (Memphis) (3.3 ± 0.9 ng m -3 ) compared with a rural/background area (1.5 ± 0.2 ng m -3 ). Due to airspace flight restrictions near the CFPP and refinery, we were unable to access near-field (stack) plumes and did not observe differences between upwind and downwind locations. Overall, this study demonstrates that highly maneuverable multicopters can be used to probe Hg concentrations aloft, which may be particularly useful for evaluating Hg emissions from remote landscapes and transient sources that are inadequately characterized and leading to uncertainties in ecosystem budgets.

  9. Aerosol trace metals, particle morphology and total gaseous mercury in the atmosphere of Oxford, UK

    Science.gov (United States)

    Witt, M. L. I.; Meheran, N.; Mather, T. A.; de Hoog, J. C. M.; Pyle, D. M.

    2010-04-01

    An investigation of atmospheric trace metals was conducted in Oxford, UK, a small city ˜60 miles northwest of London, in 2007 and 2008. Concentrations of Sr, Mo, Cd, Pb, V, Cr, Mn, Fe, Co, Ni, Cu and Zn in aerosol were measured in bulk and size segregated samples. In addition, total gaseous mercury (TGM) concentrations were monitored semi-continuously by cold vapour-atomic fluorescence spectroscopy. Metal concentrations in Oxford were intermediate between previously reported levels of UK rural and urban areas for most metals studied and levels of Cd, Ni and Pb were within European guidelines. Metal concentrations appeared to be influenced by higher traffic volume on a timescale of hours. The influence of traffic on the aerosols was also suggested by the observation of carbonaceous particles via scanning electron microscopy (SEM). Air mass back trajectories suggest air masses arriving in Oxford from London and mainland Europe contained the highest metal concentrations. Aerosol samples collected over Bonfire Weekend, a period of intense firework use and lighting of bonfires in the UK, showed metal concentrations 6-46 times higher than at other times. Strontium, a tracer of firework release, was present at higher concentrations and showed a change in its size distribution from the coarse to fine mode over Bonfire Weekend. The presence of an abundance of spherical Sr particles was also confirmed in SEM images. The average TGM concentration in Oxford was 3.17 ng m -3 (st. dev. 1.59) with values recorded between 1.32 and 23.2 ng m -3. This is a higher average value than reported from nearby rural locations, although during periods when air was arriving from the west, similar concentrations to these rural areas were seen in Oxford. Comparison to meteorological data suggests that TGM in Oxford's air is highest when wind is arriving from the east/southeast. This may be due to emissions from London/mainland Europe with a possible contribution from emissions from a local

  10. Measurements of gaseous mercury exchanges at the sediment-water, water-atmosphere and sediment-atmosphere interfaces of a tidal environment (Arcachon Bay, France).

    Science.gov (United States)

    Bouchet, Sylvain; Tessier, Emmanuel; Monperrus, Mathilde; Bridou, Romain; Clavier, Jacques; Thouzeau, Gerard; Amouroux, David

    2011-05-01

    The elemental mercury evasion from non-impacted natural areas is of significant importance in the global Hg cycle due to their large spatial coverage. Intertidal areas represent a dynamic environment promoting the transformations of Hg species and their subsequent redistribution. A major challenge remains in providing reliable data on Hg species variability and fluxes under typical transient tidal conditions found in such environment. Field experiments were thus carried out to allow the assessment and comparison of the magnitude of the gaseous Hg fluxes at the three interfaces, sediment-water, sediment-atmosphere and water-atmosphere of a mesotidal temperate lagoon (Arcachon Bay, Aquitaine, France) over three distinct seasonal conditions. The fluxes between the sediment-water and the sediment-atmosphere interfaces were directly evaluated with field flux chambers, respectively static or dynamic. Water-atmosphere fluxes were evaluated from ambient concentrations using a gas exchange model. The fluxes at the sediment-water interface ranged from -5.0 to 5.1 ng m(-2) h(-1) and appeared mainly controlled by diffusion. The occurrence of macrophytic covers (i.e.Zostera noltii sp.) enhanced the fluxes under light radiations. The first direct measurements of sediment-atmosphere fluxes are reported here. The exchanges were more intense and variable than the two other interfaces, ranging between -78 and 40 ng m(-2) h(-1) and were mostly driven by the overlying atmospheric Hg concentrations and superficial sediment temperature. The exchanges between the water column and the atmosphere, computed as a function of wind speed and gaseous mercury saturation ranged from 0.4 to 14.5 ng m(-2) h(-1). The flux intensities recorded over the intertidal sediments periodically exposed to the atmosphere were roughly 2 to 3 times higher than the fluxes of the other interfaces. The evasion of elemental mercury from emerged intertidal sediments is probably a significant pathway for Hg evasion in

  11. Determination of gaseous and particulate carbonyls (glycolaldehyde, hydroxyacetone, glyoxal, methylglyoxal, nonanal and decanal in the atmosphere at Mt. Tai

    Directory of Open Access Journals (Sweden)

    K. Kawamura

    2013-05-01

    Full Text Available Gaseous and particulate semi-volatile carbonyl compounds were determined every three hours in the atmosphere of Mount Tai (elevation, 1534 m in the North China Plain during 2–5, 23–24 and 25 June 2006 under clear sky conditions. Using a two-step filter cartridge in a series, particulate carbonyls were first collected on a quartz filter and then gaseous carbonyls were collected on a quartz filter impregnated with O-benzylhydroxylamine (BHA. After the two-step derivatization with BHA and N,O-Bis(trimethylsilyltrifluoroacetamide (BSTFA, carbonyl derivatives were measured using a gas chromatography. The gaseous concentrations were obtained as follow: glycolaldehyde (range 0–826 ng m−3, average 303 ng m−3, hydroxyacetone (0–579 ng m−3, 126 ng m−3, glyoxal (46–1200 ng m−3, 487 ng m−3, methylglyoxal (88–2690 ng m−3, 967 ng m−3, n-nonanal (0–500 ng m−3, 89 ng m−3, and n-decanal (0–230 ng m−3, 39 ng m−3. These concentrations are among the highest ever reported in the urban and forest atmosphere. We found that gaseous α-dicarbonyls (glyoxal and methylglyoxal are more than 20 times more abundant than particulate carbonyls and that glycolaldehyde is one order of magnitude more abundant than in aerosol phase. In contrast, hydroxyacetone and normal aldehydes (nonanal and decanal are equally present in both phases. Time-resolved variations of carbonyls did not show any a clear diurnal pattern, except for hydroxyacetone. We found that glyoxal, methylglyoxal and glycolaldehyde positively correlated with levoglucosan (a tracer of biomass burning, suggesting that a contribution from field burning of agricultural wastes (wheat crops is significant for the bifunctional carbonyls in the atmosphere of Mt. Tai. Upward transport of the pollutants to the mountaintop from the low lands in the North China Plain is a major process to control the distributions of carbonyls in the upper atmosphere over Mt. Tai.

  12. Transfer of gaseous iodine from atmosphere to rough rice, brown rice and polished rice

    International Nuclear Information System (INIS)

    Sumiya, Misako; Uchida, Shigeo; Muramatsu, Yasuyuki; Ohmomo, Yoichiro; Yamaguchi, Shuho; Obata, Hitoshi.

    1987-01-01

    Experiments were carried out in order to obtain information required for establishing transfer coefficients of gaseous iodine (I 2 ) to rough rice, brown rice and polished rice. The gaseous iodine deposited on young rice plants before the heading period was scarcely found in the rough rice harvested at the full ripe stage. The biological half life of iodine in hull, however, was much slower than that in leaves of 14 days. The translocation of iodine from leaves and stalks to rough rice was not clearly recognized. Therefore, it was deduced that iodine found in brown rice mainly should originate from that deposited on the hull. The distribution ratios of iodine between rough rice and brown rice, and between brown rice and polished rice were 100:4 and 100:30 on 100 grains basis, respectively. If average normalized deposition velocity (V d(m) ) or derived deposition velocity (V s ) are given, the transfer coefficients of gaseous iodine to rough rice (TF r ), brown rice (TF b ) and polished rice (TF p ) could be calculated. (author)

  13. GASEOUS MEAN OPACITIES FOR GIANT PLANET AND ULTRACOOL DWARF ATMOSPHERES OVER A RANGE OF METALLICITIES AND TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Freedman, Richard S. [SETI Institute, Mountain View, CA (United States); Lustig-Yaeger, Jacob [Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Lupu, Roxana E.; Marley, Mark S. [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, CA (United States); Lodders, Katharina, E-mail: Richard.S.Freedman@nasa.gov [Planetary Chemistry Laboratory, Washington University, St. Louis, MO (United States)

    2014-10-01

    We present new calculations of Rosseland and Planck gaseous mean opacities relevant to the atmospheres of giant planets and ultracool dwarfs. Such calculations are used in modeling the atmospheres, interiors, formation, and evolution of these objects. Our calculations are an expansion of those presented in Freedman et al. to include lower pressures, finer temperature resolution, and also the higher metallicities most relevant for giant planet atmospheres. Calculations span 1 μbar to 300 bar, and 75-4000 K, in a nearly square grid. Opacities at metallicities from solar to 50 times solar abundances are calculated. We also provide an analytic fit to the Rosseland mean opacities over the grid in pressure, temperature, and metallicity. In addition to computing mean opacities at these local temperatures, we also calculate them with weighting functions up to 7000 K, to simulate the mean opacities for incident stellar intensities, rather than locally thermally emitted intensities. The chemical equilibrium calculations account for the settling of condensates in a gravitational field and are applicable to cloud-free giant planet and ultracool dwarf atmospheres, but not circumstellar disks. We provide our extensive opacity tables for public use.

  14. Gaseous atmospheric pollution. Gas measurement; Pollution atmospherique gazeuse. Mesure des gaz

    Energy Technology Data Exchange (ETDEWEB)

    Toupance, G [Paris-12 Univ., 94 - Creteil (France); Person, A [Laboratoire d' Hygiene de la Ville de Paris, 75 (France); Le Moullec, Y; Masclet, P; Perros, P E

    2004-09-01

    This article deals with the majority of pollutants which are present in gaseous phase in the low layer of the troposphere, of the proximity of sources to the distant areas where are in weak traces persisting substances or sub-products induced by photochemical reactions. The compounds described in this article are of interest for various reasons: either they are source tracers, or they draw attention for their impact on health or/and ecosystem. Their follow-up can also be in other approaches such as the understanding of reactional mechanisms and the support to modeling of the phenomena. Thereby, the range of the covered concentrations is very large: if the preoccupations are in most of the cases to answer to detection limits of about the ppb, for some substances, the requirements can be harder and we have then to orient oneself to techniques able to quantify at the level of ppt, sometimes less. Some pollutants are qualified of 'semi-volatile', that is to say they are the property to be present in gaseous phase and in particles in suspension in air. (O.M.)

  15. Atmospheric gaseous elemental mercury (GEM concentrations and mercury depositions at a high-altitude mountain peak in south China

    Directory of Open Access Journals (Sweden)

    X. W. Fu

    2010-03-01

    Full Text Available China is regarded as the largest contributor of mercury (Hg to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China. Sources identification indicates that both regional industrial emissions and long range transport of Hg from central, south and southwest China were corresponded to the elevated GEM level. Seasonal and diurnal variations of GEM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Precipitation and throughfall deposition fluxes of THg and MeHg in Mt. Leigong were comparable or lower compared to those reported in Europe and North America, whereas litterfall deposition fluxes of THg and MeHg were higher compared to Europe and North America. This highlights the importance of vegetation to Hg atmospheric cycling. In th remote forest ecosystem of China, deposition of GEM via uptake of foliage followed by litterfall was very important for the depletion of atmospheric Hg. Elevated GEM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated litterfall deposition fluxes of Hg observed in Mt. Leigong.

  16. Radioisotope methods of investigations of phenomenons at phases border of steel - atmosphere in gaseous processes of thermochemical treatment of steel

    International Nuclear Information System (INIS)

    L'utse-Birk, A.; Bel'ski, V.; Vez'ranovski, Eh.; Valis', L.

    1979-01-01

    Radioisotope methods of investigations of the processes of thermochemical treatment of steels are valuable, and in some cases, the only means for analysis of complicated mechanisms of diffusion, absorption and chemical reactions, going on in some technological processes. New specific methods are stated for investigation of processes on the border between steel and gaseous atmosphere. Quantative method nas been developed for investigation of the kinetics of carbon transfere (labelled by carbon-14) from steel into gases. Hydrocarbons and their derivatives are adsorbed selectivelly and beta-activity of the compound is measured in the presence of liquid scintillators. Limiting detectable amount of carbon equals to 0.5μg. Application of labelled (by radioisotope iron-59) iron in steel has ensured a possibility to determine its participation in reactions with chromium and titanum coating atmospheres. Application of hydrocarbons labelled by carbon-14 in the composition of titanum coating atmosphere has permitted to determine, in comparison with investigation of carbon diffusion in steel, participation of two different carbon sources in the forming of the TiC layer on steel and has led to the optimization of processes, especially for low-carbon steels [ru

  17. Atmospheric contamination by pesticides: Determination in the liquid, gaseous and particulate phases.

    Science.gov (United States)

    Millet, M; Wortham, H; Sanusi, A; Mirabel, P

    1997-01-01

    Between 1991 and 1993, 18 fogwater samples, 31 rainwater samples and 17 atmosphere (gas and particles) samples were analysed for 13 pesticides (pp'DDT,pp'DDD,pp'DDE, aldrin, dieldrin, lindane, hexachlorobenzene, fenpropathrin, mecoprop, methyl-parathion, atrazine, isoproturon and aldicarb). The samples were collected in a rural area where some of the compounds are in use (experimental INRA farm, "Institut National de la Recherche Agronomique" in Colmar, Eastern France, 80,000 inhabitants). This paper briefly presents the analytical methodology used and, in detail, the contamination level of the different atmospheric phases. The contamination levels are roughly constant throughout the year in all the atmospheric phases and the most abundant pesticides are those commonly used on the experimental INRA farm and other surrounding farms. Nevertheless, some pesticides not used since the 1970s such as 1,1-Bis(4-chlorophenyl)-2,2,2-trichloroethane (pp'DDT) and 2,2-Bis(4-chlorophenyl)-1,1-dichloroethane (pp 'DDD) are also detected in the atmosphere of Colmar. A small increase in the pesticide concentrations in the atmosphere (gas and particles) was observed during treatments.

  18. Seasonal and diel patterns of total gaseous mercury concentration in the atmosphere of the Central Valley of Costa Rica

    International Nuclear Information System (INIS)

    Castillo, Aylin; Valdes, Juan; Sibaja, Jose; Vega, Ilena; Alfaro, Rosa; Morales, Jose; Esquivel, Germain; Barrantes, Elisa; Black, Paleah; Lean, David

    2011-01-01

    Research highlights: → Elevated seasonal and daily patterns of total gaseous mercury (TGM) were observed in the Central Valley of Costa Rica 27 km south-east of the Poas volcano. → With the onset of the wet season TGM in late April, values increased from typical values near 10 to 905 ng m -3 . → During the day, TGM values increased until midday along with temperature and radiation but relative humidity showed a reciprocal pattern. → We conclude that elemental mercury from the volcano may react with atmospheric oxidants especially during the dry season and the mercury would be deposited to the ground. → With the onset of heavy rains, mercury in the soil is reduced and re-volatilized resulting in the high levels in atmospheric air at the end of April. - Abstract: Monitoring of Hg in the atmosphere near volcanoes is limited with no previous data for Costa Rica. Seasonal and daily patterns of total gaseous mercury (TGM) were observed at the main sampling location at the Universidad Nacional, Heredia, Costa Rica. The area (lat. 10.000230 long. -84.109499) is located in the Central Valley of Costa Rica and is 27 km SE of the Poas volcano (lat. 10.199486 long. -84.231388). Measurements were made from May 2008 to May 2009 at this location with some additional values obtained at other sites near the Poas volcano including San Luis and Grecia as well as near, Turrialba and Irazu volcanoes. Total gaseous Hg was determined in samples collected at a height of 2 m using the Tekran 2537A (Tekran Inc.) gas-phase Hg vapor analyzer. Meteorological data (temperature, relative humidity, wind speed, wind direction, radiation and precipitation) were obtained from the airport weather station located at Alajuela. Monthly precipitation is typically 85 mm during the dry season (December to April) with winds from the west. The wet season begins in late April and continues to December with monthly rainfall of 328 mm and winds from the NE. The annual mean temperature is 20 deg. C

  19. Seasonal and diel patterns of total gaseous mercury concentration in the atmosphere of the Central Valley of Costa Rica

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Aylin; Valdes, Juan; Sibaja, Jose; Vega, Ilena; Alfaro, Rosa; Morales, Jose; Esquivel, Germain; Barrantes, Elisa [Laboratory for Atmospheric Chemistry, LAQAT-UNA, Universidad Nacional, P.O. Box 86-3000, Heredia (Costa Rica); Black, Paleah [Department of Biology, University of Ottawa, P.O. Box 450 Station A, Ottawa, Ontario, K1N 6N5 (Canada); Lean, David, E-mail: drslean@gmail.com [P.O. Box 309, Apsley, Ontario, K0L 1A0 (Canada)

    2011-02-15

    Research highlights: {yields} Elevated seasonal and daily patterns of total gaseous mercury (TGM) were observed in the Central Valley of Costa Rica 27 km south-east of the Poas volcano. {yields} With the onset of the wet season TGM in late April, values increased from typical values near 10 to 905 ng m{sup -3}. {yields} During the day, TGM values increased until midday along with temperature and radiation but relative humidity showed a reciprocal pattern. {yields} We conclude that elemental mercury from the volcano may react with atmospheric oxidants especially during the dry season and the mercury would be deposited to the ground. {yields} With the onset of heavy rains, mercury in the soil is reduced and re-volatilized resulting in the high levels in atmospheric air at the end of April. - Abstract: Monitoring of Hg in the atmosphere near volcanoes is limited with no previous data for Costa Rica. Seasonal and daily patterns of total gaseous mercury (TGM) were observed at the main sampling location at the Universidad Nacional, Heredia, Costa Rica. The area (lat. 10.000230 long. -84.109499) is located in the Central Valley of Costa Rica and is 27 km SE of the Poas volcano (lat. 10.199486 long. -84.231388). Measurements were made from May 2008 to May 2009 at this location with some additional values obtained at other sites near the Poas volcano including San Luis and Grecia as well as near, Turrialba and Irazu volcanoes. Total gaseous Hg was determined in samples collected at a height of 2 m using the Tekran 2537A (Tekran Inc.) gas-phase Hg vapor analyzer. Meteorological data (temperature, relative humidity, wind speed, wind direction, radiation and precipitation) were obtained from the airport weather station located at Alajuela. Monthly precipitation is typically 85 mm during the dry season (December to April) with winds from the west. The wet season begins in late April and continues to December with monthly rainfall of 328 mm and winds from the NE. The annual mean

  20. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    KAUST Repository

    Arrieta, J M; Duarte, Carlos M.; Sala, M. Montserrat; Dachs, Jordi

    2016-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  1. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean

    KAUST Repository

    Arrieta, Jesus

    2016-01-20

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  2. Out of Thin Air: Microbial Utilization of Atmospheric Gaseous Organics in the Surface Ocean.

    Science.gov (United States)

    Arrieta, Jesús M; Duarte, Carlos M; Sala, M Montserrat; Dachs, Jordi

    2015-01-01

    Volatile and semi-volatile gas-phase organic carbon (GOC) is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 and 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidizing marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  3. Out of thin air: Microbial utilization of atmospheric gaseous organics in the surface ocean

    Directory of Open Access Journals (Sweden)

    Jesus M Arrieta

    2016-01-01

    Full Text Available Volatile and semi-volatile gas-phase organic carbon (GOC is a largely neglected component of the global carbon cycle, with poorly resolved pools and fluxes of natural and anthropogenic GOC in the biosphere. Substantial amounts of atmospheric GOC are exchanged with the surface ocean, and subsequent utilization of specific GOC compounds by surface ocean microbial communities has been demonstrated. Yet, the final fate of the bulk of the atmospheric GOC entering the surface ocean is unknown. Our data show experimental evidence of efficient use of atmospheric GOC by marine prokaryotes at different locations in the NE Subtropical Atlantic, the Arctic Ocean and the Mediterranean Sea. We estimate that between 2 to 27% of the prokaryotic carbon demand was supported by GOC with a major fraction of GOC inputs being consumed within the mixed layer. The role of the atmosphere as a key vector of organic carbon subsidising marine microbial metabolism is a novel link yet to be incorporated into the microbial ecology of the surface ocean as well as into the global carbon budget.

  4. Preliminary results from a continuous record of atmospheric gaseous mercury at the coastal station Dumont d’Urville in Antarctica

    Directory of Open Access Journals (Sweden)

    Dommergue A.

    2013-04-01

    Full Text Available While the tropospheric reactivity of mercury (Hg in the Arctic is more and more documented only a few attempts were made to study the Hg cycle in the Southern Polar Regions. The role of the Antarctic continent and its influence on the global geochemical cycle of mercury is unclear today, and is certainly under evaluated by current models. Here, we present the first continuous high-time-resolution measurements of atmospheric gaseous elemental mercury (GEM in East Antarctica from February 2010 to March 2011 at the coastal research station Dumont d’Urville (DDU (66°40’S, 140°01’E, 43 m asl. We report an annual mean level of 1.062 ± 0.321 ng/m3 with well-marked daily fluctuations from October to January. An intense reactivity originated from the atmospheric boundary layer of the Antarctic plateau under sunlight conditions is observed at DDU. Partly GEM-depleted air masses are exported from the continent and dramatically influence the GEM record at DDU. From November to January, surface waters of the Southern Ocean are an important source of GEM.

  5. A review of the rates of reaction of unirradiated uranium in gaseous atmospheres

    International Nuclear Information System (INIS)

    Pearce, R.J.

    1989-10-01

    The review collates available quantitative rate data for the reaction of unirradiated uranium in dry and moist air, steam and carbon dioxide based atmospheres at temperatures ranging from room temperature to above the melting point of uranium. Reactions in nitrogen and carbon monoxide are also considered. The aim of the review is to provide a compilation of base data for the hazard analysis of fault conditions relating to Magnox fuel. (author)

  6. Deposition velocity of gaseous organic iodine from the atmosphere to rice plants

    International Nuclear Information System (INIS)

    Muramatsu, Yasuyuki; Shigeo-Uchida; Sumiya, Misako; Ohmomo, Yoichiro

    1996-01-01

    To obtain parameter values for the assessment of 129 I transfer from the atmosphere to rice, deposition of CH 3 I to rice plants has been studied. The mass normalized deposition velocity (V D ) of CH 3 I for rough (unhulled) rice was 0.00048 cm 3 g -1 s -1 , which is about 1/300 of that of I 2 . Translocation of iodine, deposited as CH 3 I on leaves and stems, to rice grain was negligibly small. Distribution of iodine between hull and inner part of the grain was found to depend also on the chemical forms of atmospheric iodine to be deposited. The ratio of the iodine distribution in a grain exposed to CH 3 I was as follows: rough rice: brown rice (hulled rice):polished rice = 1.0:0.49:0.38. The distribution ratio in polished grains for CH 3 I exposed rice was about 20 times higher than that for I 2 . 22 refs., 1 fig., 6 tabs

  7. Diffusion model of solid particles in a gaseous atmosphere. Pt. 1

    International Nuclear Information System (INIS)

    Fernandez Ruiz, J.L.

    1987-01-01

    Starting from Voinov and Garipov's lagrangian statements on the problem of dynamic evolution of bubbles in liquids, this work is trying to determine some diffusion equations of solid particles in little dense matter like gases or liquids, aiming at applying it to the tracing of matter in atmospheric diffusion and the tracing of corpuscles in liquids. All the resulting equations lead to a solution given as a tensor θ ij related to the velocity states v i defined as v i = , and to the potential from which derive. One has had in mind the factor of mutual correlation between the diffusing particles. This increases the scope of application of these equations to Chemistry and to Biomedical Sciences. (author)

  8. Simultaneous analysis of gaseous and particulate sulphur in the atmosphere by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Matsuda, Yatsuka; Mamuro, Tetsuo

    1975-01-01

    An analytical technique for the simultaneous measurements of the atmospheric concentrations of SO 2 gas and sulphur absorbed by aerosol particles has been developed. Aerosol particles are collected on membrane filter and at the same time SO 2 gas is captured on alkali impregnated filter. The sulphur content in each filter is measured by an energy dispersive X -ray fluorescence spectrometer consisting of a Si(Li) semiconductor detector connected to a multi-channel pulse height analyzer and an excitation source of 55 Fe. Two methods are acceptable for the determination of the sulphur content in impregnated filter by X-ray fluorescence analysis. In the first method X-ray fluorescence analysis is made after the collected sulphur gas diffused and distributed uniformly enough throughout the filter, and in the second method X-ray fluorescence analysis gas to be finished before the diffusion of the collected sulphur becomes appreciable. (author)

  9. Characterization of gaseous species in scanning atmospheric rf plasma with transmission infrared spectroscopy

    International Nuclear Information System (INIS)

    Kim, Seong H.; Kim, Jeong Hoon; Kang, Bang-Kwon

    2008-01-01

    A scanning atmospheric radio-frequency (rf) plasma was analyzed with transmission infrared (IR) spectroscopy. The IR analyses were made for the plasmas used for hydrophobic coating deposition and superhydrophobic coating deposition processes. Since the rf plasma was generated in a small open space with a high gas flow rate in ambient air, the density of gas-phase molecules was very high and the plasma-generated reactive species seemed to undergo various reactions in the gas phase. So, the transmission IR spectra of the scanning atmospheric rf plasma were dominated by gas-phase reaction products, rather than plasma-generated intermediate species. In the CH 4 /He plasma used for hydrophobic coating deposition, C 2 H 6 , C 2 H 2 , and a small amount of C 2 H 4 as well as CO were detected in transmission IR. The intensities of these peaks increased as the rf power increased. The CO formation is due to the activation of oxygen and water in the air. In the CF 4 /H 2 /He plasma used for deposition of superhydrophobic coatings, C 2 F 6 , CF 3 H, COF 2 , and HF were mainly detected. When the H 2 /CF 4 ratio was ∼0.5, the consumption of CF 4 was the highest. As the H 2 /CF 4 ratio increased higher, the C 2 F 6 production was suppressed while the CF 3 H peak grew and the formation of CH 4 were detected. In both CH 4 /He and CF 4 /H 2 /He plasma systems, the undissociated feed gas molecules seem to be highly excited vibrationally and rotationally. The information on plasma-generated reactive species and their reactions was deduced from the distribution of these gas-phase reaction products

  10. "Sizing" Heterogeneous Chemistry in the Conversion of Gaseous Dimethyl Sulfide to Atmospheric Particles.

    Science.gov (United States)

    Enami, Shinichi; Sakamoto, Yosuke; Hara, Keiichiro; Osada, Kazuo; Hoffmann, Michael R; Colussi, Agustín J

    2016-02-16

    The oxidation of biogenic dimethyl sulfide (DMS) emissions is a global source of cloud condensation nuclei. The amounts of the nucleating H2SO4(g) species produced in such process, however, remain uncertain. Hydrophobic DMS is mostly oxidized in the gas phase into H2SO4(g) + DMSO(g) (dimethyl sulfoxide), whereas water-soluble DMSO is oxidized into H2SO4(g) in the gas phase and into SO4(2-) + MeSO3(-) (methanesulfonate) on water surfaces. R = MeSO3(-)/(non-sea-salt SO4(2-)) ratios would therefore gauge both the strength of DMS sources and the extent of DMSO heterogeneous oxidation if Rhet = MeSO3(-)/SO4(2-) for DMSO(aq) + ·OH(g) were known. Here, we report that Rhet = 2.7, a value obtained from online electrospray mass spectra of DMSO(aq) + ·OH(g) reaction products that quantifies the MeSO3(-) produced in DMSO heterogeneous oxidation on aqueous aerosols for the first time. On this basis, the inverse R dependence on particle radius in size-segregated aerosol collected over Syowa station and Southern oceans is shown to be consistent with the competition between DMSO gas-phase oxidation and its mass accommodation followed by oxidation on aqueous droplets. Geographical R variations are thus associated with variable contributions of the heterogeneous pathway to DMSO atmospheric oxidation, which increase with the specific surface area of local aerosols.

  11. Identification of potential regional sources of atmospheric total gaseous mercury in Windsor, Ontario, Canada using hybrid receptor modeling

    Directory of Open Access Journals (Sweden)

    X. Xu

    2010-08-01

    Full Text Available Windsor (Ontario, Canada experiences trans-boundary air pollution as it is located on the border immediately downwind of industrialized regions of the United States of America. A study was conducted in 2007 to identify the potential regional sources of total gaseous mercury (TGM and investigate the effects of regional sources and other factors on seasonal variability of TGM concentrations in Windsor.

    TGM concentration was measured at the University of Windsor campus using a Tekran® 2537A Hg vapour analyzer. An annual mean of 2.02±1.63 ng/m3 was observed in 2007. The average TGM concentration was high in the summer (2.48±2.68 ng/m3 and winter (2.17±2.01 ng/m3, compared to spring (1.88±0.78 ng/m3 and fall (1.76±0.58 ng/m3. Hybrid receptor modeling potential source contribution function (PSCF was used by incorporating 72-h backward trajectories and measurements of TGM in Windsor. The results of PSCF were analyzed in conjunction with the Hg emissions inventory of North America (by state/province to identify regions affecting Windsor. In addition to annual modeling, seasonal PSCF modeling was also conducted. The potential source region was identified between 24–61° N and 51–143° W. Annual PSCF modeling identified major sources southwest of Windsor, stretching from Ohio to Texas. The emissions inventory also supported the findings, as Hg emissions were high in those regions. Results of seasonal PSCF modeling were analyzed to find the combined effects of regional sources, meteorological conditions, and surface re-emissions, on seasonal variability of Hg concentrations. It was found that the summer and winter highs of atmospheric Hg can be attributed to areas where large numbers of coal fired power plants are located in the USA. Weak atmospheric dispersion due to low winds and high re-emission from surfaces due to higher temperatures also contributed to high concentrations in

  12. Evaluation of mechanism of cold atmospheric pressure plasma assisted polymerization of acrylic acid on low density polyethylene (LDPE) film surfaces: Influence of various gaseous plasma pretreatment

    Science.gov (United States)

    Ramkumar, M. C.; Pandiyaraj, K. Navaneetha; Arun Kumar, A.; Padmanabhan, P. V. A.; Uday Kumar, S.; Gopinath, P.; Bendavid, A.; Cools, P.; De Geyter, N.; Morent, R.; Deshmukh, R. R.

    2018-05-01

    Owing to its exceptional physiochemical properties, low density poly ethylene (LDPE) has wide range of tissue engineering applications. Conversely, its inadequate surface properties make LDPE an ineffectual candidate for cell compatible applications. Consequently, plasma-assisted polymerization with a selected precursor is a good choice for enhancing its biocompatibility. The present investigation studies the efficiency of plasma polymerization of acrylic acid (AAC) on various gaseous plasma pretreated LDPE films by cold atmospheric pressure plasma, to enhance its cytocompatibility. The change in chemical composition and surface topography of various gaseous plasma pretreated and acrylic deposited LDPE films has been assessed by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The changes in hydrophilic nature of surface modified LDPE films were studied by contact angle (CA) analysis. Cytocompatibility of the AAC/LDPE films was also studied in vitro, using RIN-5F cells. The results acquired by the XPS and AFM analysis clearly proved that cold atmospheric pressure (CAP) plasma assisted polymerization of AAC enhances various surface properties including carboxylic acid functional group density and increased surface roughness on various gaseous plasma treated AAC/LDPE film surfaces. Moreover, contact angle analysis clearly showed that the plasma polymerized samples were hydrophilic in nature. In vitro cytocompatibility analysis undoubtedly validates that the AAC polymerized various plasma pretreated LDPE films surfaces stimulate cell distribution and proliferation compared to pristine LDPE films. Similarly, cytotoxicity analysis indicates that the AAC deposited various gaseous plasma pretreated LDPE film can be considered as non-toxic as well as stimulating cell viability significantly. The cytocompatible properties of AAC polymerized Ar + O2 plasma pretreated LDPE films were found to be more pronounced compared to the other plasma pretreated

  13. Development of a gas chromatography-mass spectrometry method for the determination of pesticides in gaseous and particulate phases in the atmosphere

    International Nuclear Information System (INIS)

    Borras, E.; Sanchez, P.; Munoz, A.; Tortajada-Genaro, L.A.

    2011-01-01

    Highlights: → An efficient method for the determination of sixteen pesticides in atmospheric samples. → XAD-4 is an interesting support for collecting gas-phase pesticides, with similar performances than the conventional XAD-2. → The ultrasonic extraction is cheaper, less aggressive and time-consuming with excellent analytical parameters. → The method has been successfully tested by using high volume atmospheric simulation chamber and field campaigns. - Abstract: A reliable multi-residue method for determining gaseous and particulate phase pesticides in atmospheric samples has been developed. This method, based on full scan gas chromatography-mass spectrometry (GC-MS), allowed the proper determination of sixteen relevant pesticides, in a wide range of concentrations and without the influence of interferences. The pesticides were benfluralin, bitertanol, buprofezin, chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, ethalfluralin, fenthion, lindane, malathion, methidathion, propachlor, propanil, pyriproxifen, tebuconazol and trifluralin. Comparisons of two types of sampling filters (quartz and glass fibre) and four types of solid-phase cartridges (XAD-2, XAD-4, Florisil and Orbo-49P) showed that the most suitable supports were glass fibre filter for particulate pesticides and XAD-2 and XAD-4 cartridges for gaseous pesticides (>95% recovery). Evaluations of elution solvents for ultrasonic-assisted extraction demonstrated that isooctane is better than ethylacetate, dichloromethane, methanol or a mixture of acetone:hexane (1:1). Recovery assays and the standard addition method were performed to validate the proposed methodology. Moreover, large simulator chamber experiments allowed the best study of the gas-particle partitioning of pesticides for testing the sampling efficiency for the validation of an analytical multiresidue method for pesticides in air. Satisfactory analytical parameters were obtained, with a repeatability of 5 ± 1%, a reproducibility of 13

  14. Steady state transient analysis of spent nuclear fuel bundle exposed to stagnant gaseous atmosphere (Paper No. HMT-56-87)

    International Nuclear Information System (INIS)

    Pal, G.; Markandeya, S.G.; Venkatraj, V.

    1987-01-01

    This paper deals with the development of a computer code for the analysis of radiative heat exchange in rod bundles. Nuclear fuel bundles continue to generate heat even after their removal from the reactor core because of decay of fission products. During the transfer of the bundles from the core to storage bay they may pass through gaseous environment. Radiative heat exchange will be the dominant mode within the bundle under this condition. A computer code RIIEINA (Radiative Heat Exchange In Nuclear Assemblies) has been developed and used for predicting the behaviour of the spent fuel subassembly of the proposed Prototype Fast Breeder Reactor exposed to gaseous environment. The analytical model computer code and the results obtained are briefly discussed. (author). 5 refs., 5 figs

  15. Seasonal atmospheric deposition and air-sea gaseous exchange of polycyclic aromatic hydrocarbons over the Yangtze River Estuary, East China Sea: Implication for the source-sink processes

    Science.gov (United States)

    Jiang, Y.; Guo, Z.

    2017-12-01

    As the home of the largest port in the world, the Yangtze River Estuary (YRE) in the East China Sea (ECS) is adjacent to the largest economic zone in China with more than 10% of Chinese population and provides one-fifth of national GDP. The YRE is under the path of contaminated East Asian continental outflow. These make the YRE unique for the pollutant biogeochemical cycling in the world. In this work, 94 pairs of air samples and 20 surface seawater samples covering four seasons were collected from a remote receptor site in the YRE from March 2014 to January 2015, in order to explore the seasonal fluxes of air-sea gaseous exchange and atmospheric dry and wet deposition of 15 polycyclic aromatic hydrocarbons (PAHs) and their source-sink processes at the air-sea interface. The average dry and wet deposition fluxes of 15 PAHs were estimated as 879 ± 1393 ng m-2 d-1 and 755 ± 545 ng m-2 d-1, respectively. The gaseous PAHs were released from seawater to atmosphere during the whole year with an average of 3039 ± 2030 ng m-2 d-1. The gaseous exchange of PAHs was referred as the dominant process at the air-sea interface in the YRE as the magnitude of volatilization flux of PAHs exceeded that of the total dry and wet deposition. The gaseous PAH exchange flux was dominated by 3-ring PAHs, with the highest value in summer while lowest in winter, depicting a strong seasonal variation due to temperature, wind speed and air-sea concentration gradient difference among seasons. Based on the simplified mass balance estimation, net 9.6 tons/y of PAHs was volatilized from seawater to atmosphere with an area of approximately 20000 km2 in the YRE. Apart from Yangtze River input and ocean ship emissions in the entire year, the selective release of low molecular weight PAHs from sediments in winter due to re-suspension triggered by the East Asian winter monsoon could be another possible source for dissolved PAHs. This work suggests that the source-sink processes of PAHs at air

  16. Observations of speciated atmospheric mercury at three sites in Nevada: Evidence for a free tropospheric source of reactive gaseous mercury

    OpenAIRE

    Weiss-Penzias, Peter; Gustin, Mae Sexauer; Lyman, Seth

    2009-01-01

    Air mercury (Hg) speciation was measured for 11 weeks (June–August 2007) at three sites simultaneously in Nevada, USA. Mean reactive gaseous Hg (RGM) concentrations were elevated at all sites relative to those reported for locations not directly influenced by known point sources. RGM concentrations at all sites displayed a regular diel pattern and were positively correlated with ozone (O3) and negatively correlated with elemental Hg (Hg0) and dew point temperature (Tdp). Superimposed on the d...

  17. Theoretical study of the thermochemical properties of gaseous iodine compounds: incidences in atmospheric chemistry and nuclear safety

    International Nuclear Information System (INIS)

    Louis, F.; Fortin, C.; Cornet, M.; Khanniche, S.; Skoviera, J.; Cantrel, L.; Cernusak, I.

    2015-07-01

    Thermochemical properties (ΔfH 0 298K , S 0 298K et C p = f(T)) have been determined for a series of gaseous iodine-containing compounds by using quantum chemistry tools. Different levels of theory have been employed in this work in order to predict geometrical parameters and the energetics including spin-orbit coupling. The use of the B3LYP functional for the geometry optimization followed by a calculation of the total electronic energies using the Dual Level method allows to her standard enthalpies of formation at 298 K in good agreement with the available literature data. (authors)

  18. Development of a gas chromatography-mass spectrometry method for the determination of pesticides in gaseous and particulate phases in the atmosphere.

    Science.gov (United States)

    Borrás, E; Sánchez, P; Muñoz, A; Tortajada-Genaro, L A

    2011-08-05

    A reliable multi-residue method for determining gaseous and particulate phase pesticides in atmospheric samples has been developed. This method, based on full scan gas chromatography-mass spectrometry (GC-MS), allowed the proper determination of sixteen relevant pesticides, in a wide range of concentrations and without the influence of interferences. The pesticides were benfluralin, bitertanol, buprofezin, chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, ethalfluralin, fenthion, lindane, malathion, methidathion, propachlor, propanil, pyriproxifen, tebuconazol and trifluralin. Comparisons of two types of sampling filters (quartz and glass fibre) and four types of solid-phase cartridges (XAD-2, XAD-4, Florisil and Orbo-49P) showed that the most suitable supports were glass fibre filter for particulate pesticides and XAD-2 and XAD-4 cartridges for gaseous pesticides (>95% recovery). Evaluations of elution solvents for ultrasonic-assisted extraction demonstrated that isooctane is better than ethylacetate, dichloromethane, methanol or a mixture of acetone:hexane (1:1). Recovery assays and the standard addition method were performed to validate the proposed methodology. Moreover, large simulator chamber experiments allowed the best study of the gas-particle partitioning of pesticides for testing the sampling efficiency for the validation of an analytical multiresidue method for pesticides in air. Satisfactory analytical parameters were obtained, with a repeatability of 5±1%, a reproducibility of 13±3% and detection limits of 0.05-0.18 pg m(-3) for the particulate phase and 26-88 pg m(-3) for the gaseous phase. Finally, the methodology was successfully applied to rural and agricultural samples in the Mediterranean area. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Development of a gas chromatography-mass spectrometry method for the determination of pesticides in gaseous and particulate phases in the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Borras, E.; Sanchez, P.; Munoz, A. [Instituto Universitario Centro de Estudios Ambientales del Mediterraneo CEAM-UMH (Fundacion CEAM-UMH), 46980 Paterna, Valencia (Spain); Tortajada-Genaro, L.A., E-mail: luitorge@qim.upv.es [Instituto IDM, Departamento de Quimica, Universitat Politecnica de Valencia, Cami de Vera s/n 46022 Valencia (Spain)

    2011-08-05

    Highlights: {yields} An efficient method for the determination of sixteen pesticides in atmospheric samples. {yields} XAD-4 is an interesting support for collecting gas-phase pesticides, with similar performances than the conventional XAD-2. {yields} The ultrasonic extraction is cheaper, less aggressive and time-consuming with excellent analytical parameters. {yields} The method has been successfully tested by using high volume atmospheric simulation chamber and field campaigns. - Abstract: A reliable multi-residue method for determining gaseous and particulate phase pesticides in atmospheric samples has been developed. This method, based on full scan gas chromatography-mass spectrometry (GC-MS), allowed the proper determination of sixteen relevant pesticides, in a wide range of concentrations and without the influence of interferences. The pesticides were benfluralin, bitertanol, buprofezin, chlorfenvinphos, chlorpyrifos, chlorpyrifos-methyl, ethalfluralin, fenthion, lindane, malathion, methidathion, propachlor, propanil, pyriproxifen, tebuconazol and trifluralin. Comparisons of two types of sampling filters (quartz and glass fibre) and four types of solid-phase cartridges (XAD-2, XAD-4, Florisil and Orbo-49P) showed that the most suitable supports were glass fibre filter for particulate pesticides and XAD-2 and XAD-4 cartridges for gaseous pesticides (>95% recovery). Evaluations of elution solvents for ultrasonic-assisted extraction demonstrated that isooctane is better than ethylacetate, dichloromethane, methanol or a mixture of acetone:hexane (1:1). Recovery assays and the standard addition method were performed to validate the proposed methodology. Moreover, large simulator chamber experiments allowed the best study of the gas-particle partitioning of pesticides for testing the sampling efficiency for the validation of an analytical multiresidue method for pesticides in air. Satisfactory analytical parameters were obtained, with a repeatability of 5 {+-} 1%, a

  20. Gaseous nebulae

    International Nuclear Information System (INIS)

    Williams, R.E.

    1976-01-01

    Gaseous nebulae are large, tenuous clouds of ionized gas that are associated with hot stars and that emit visible light because of the energy that they receive from the ultraviolet radiation of the stars. Examples include H II regions, planetary nebulae, and nova/supernova remnants. The emphasis is on the physical processes that occur in gaseous nebulae as opposed to a study of the objects themselves. The introduction discusses thermodynamic vs. steady-state equilibrium and excitation conditions in a dilute radiation field. Subsequent sections take up important atomic processes in gaseous nebulae (particle--particle collision rates, radiative interaction rates, cross sections), the ionization equilibrium (sizes of H II regions, ionization of the heavier elements), kinetic temperature and energy balance (heating of the electrons, cooling of the electrons), and the spectra of gaseous nebulae (line fluxes in nebulae). 7 figures, 5 tables

  1. Observations of speciated atmospheric mercury at three sites in Nevada: Evidence for a free tropospheric source of reactive gaseous mercury

    Science.gov (United States)

    Weiss-Penzias, Peter; Gustin, Mae Sexauer; Lyman, Seth N.

    2009-07-01

    Air mercury (Hg) speciation was measured for 11 weeks (June-August 2007) at three sites simultaneously in Nevada, USA. Mean reactive gaseous Hg (RGM) concentrations were elevated at all sites relative to those reported for locations not directly influenced by known point sources. RGM concentrations at all sites displayed a regular diel pattern and were positively correlated with ozone (O3) and negatively correlated with elemental Hg (Hg0) and dew point temperature (Tdp). Superimposed on the diel changes were 2- to 7-day periods when RGM concentrations increased across all three sites, producing significant intersite correlations of RGM daily means (r = 0.53-0.76, p distribution (GFD) plots and determine trajectory residence times (TRT) in specific source boxes. The GFD for the upper-quartile RGM daily means at one site showed a contributing airflow regime from the high-altitude subtropics with little precipitation, while that developed for the lower-quartile RGM concentrations indicated predominantly lower-altitude westerly flow and precipitation. Daily mean TRT in a subtropical high-altitude source box (>2 km and RGM at two sites (r2 = 0.37 and 0.27, p RGM from the free troposphere is a potentially important component of Hg input to rural areas of the western United States.

  2. Influence of in-port ships emissions to gaseous atmospheric pollutants and to particulate matter of different sizes in a Mediterranean harbour in Italy

    Science.gov (United States)

    Merico, E.; Donateo, A.; Gambaro, A.; Cesari, D.; Gregoris, E.; Barbaro, E.; Dinoi, A.; Giovanelli, G.; Masieri, S.; Contini, D.

    2016-08-01

    Ship emissions are a growing concern, especially in coastal areas, for potential impacts on human health and climate. International mitigation strategies to curb these emission, based on low-sulphur content fuels, have proven useful to improve local air quality. However, the effect on climate forcing is less obvious. Detailed information on the influence of shipping to particles of different sizes is needed to investigate air quality and climate interaction. In this work, the contributions of maritime emissions to atmospheric concentrations of gaseous pollutants (NO, NO2, SO2, and O3) and of particles (sizes from 0.009 μm to 30 μm) were investigated considering manoeuvring (arrival and departure of ships) and hotelling phases (including loading/unloading activities). Results showed that the size distributions of shipping contributions were different for the two phases and could be efficiently described, using measured data, considering four size-ranges. The largest contribution to particles concentration was observed for Dp hotelling for size range 0.4-1 μm. The comparison of 2012 and 2014 datasets showed no significant changes of gaseous and particulate pollutant emissions and of the contribution to particle mass concentration. However, an increase of the contribution to particle number concentration (PNC) was observed. Results suggested that harbour logistic has a relevant role in determining the total impact of shipping on air quality of the nearby coastal areas. Additionally, future policies should focus on PNC that represents an important fraction of emissions also for low-sulphur fuels. DOAS remote sensing proved a useful tool to directly measure NO2 and SO2 ship emissions giving estimates comparable with those of emission inventory approach.

  3. Gaseous Matter

    CERN Document Server

    Angelo, Joseph A

    2011-01-01

    aseous Matter focuses on the many important discoveries that led to the scientific interpretation of matter in the gaseous state. This new, full-color resource describes the basic characteristics and properties of several important gases, including air, hydrogen, helium, oxygen, and nitrogen. The nature and scope of the science of fluids is discussed in great detail, highlighting the most important scientific principles upon which the field is based. Chapters include:. Gaseous Matter An Initial Perspective. Physical Characteristics of Gases. The Rise of the Science of Gases. Kinetic Theory of

  4. Simultaneous analyses of gaseous and particulate sulphur compounds in the atmosphere by x-ray fluorescence spectrometry, (1)

    International Nuclear Information System (INIS)

    Matsuda, Yatsuka; Mamuro, Tetsuo

    1974-01-01

    An analytical technique for the simultaneous measurements of the atmospheric concentrations of SO 2 gas and sulphur absorbed by aerosol particles has been developed. Aerosol particles are collected on membrane filter and at the same time SO 2 gas is captured on alkali impregnated filter. The sulphur content in each filter is measured by an energy dispersive X-ray fluorescence spectrometer consisting of a Si(Li) semiconductor detector connected to a multichannel pulse hight analyzer and an excitation source of 55 Fe. Two methods are acceptable for the determination of the sulphur content in impregnated filter by X-ray fluorescence analysis. In the first method X-ray fluorescence analysis is made after the collected sulphur has diffused and distributed uniformly enough throughout filter, and in the second method X-ray fluorescence analysis has to be finished before the diffusion of the collected sulphur becomes appreciable. (auth.)

  5. Experimental study of the aluminum droplet combustion under forced convection. Influence of the gaseous atmosphere; Etude experimentale de la combustion des gouttes d'aluminium en convection forcee. Influence de l'atmosphere gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Sarou-Kanian, V.

    2003-12-15

    Because of its high energetic power, the combustion of aluminum particles in solid propellant rocket motors improves the efficiency of heavy-lift launcher as Ariane 5. Aluminum particles burn in a gaseous atmosphere essentially composed of H{sub 2}O, CO{sub 2}, N{sub 2}, HCl, H{sub 2}, and CO, at high pressure (P=60-70 atm) and high temperature (T>3000 K). In the present work, we have been particularly interested in the influence of the gaseous atmosphere on the different burning processes both in the gas-phase and at the aluminum droplet surface. An experimental set-up was developed in order to describe precisely, thanks to several analysis techniques (high-speed camera, pyrometry, spectrometry, SEM, nuclear activation) the combustion of aerodynamically levitated millimetric aluminum droplets in gas mixtures with compositions close to the propellant ones (H{sub 2}O, CO{sub 2}, N{sub 2}). The main result is that each species plays a different role in the aluminum combustion. The water vapor has the biggest influence in the gas-phase process due to the production of hydrogen facilitating the heat and mass diffusion between the flame and the droplet. Nitrogen is essentially acting in surface reactions with the formation of aluminum nitride (AlN) and oxynitride (AlON) which may completely cover the droplet and stop the gas-phase combustion. Carbon dioxide has a double effect. On the one hand, CO{sub 2} burns in the flame, but it is less efficient than H{sub 2}O because the heat and mass transfer properties are poorer for CO than for H{sub 2}. On the other hand, a carbon dissolution phenomenon occurs in the aluminum droplet during burning which may reach saturation (20-25% molar) and involves a carbon rejection at the surface leading to the end of the gas-phase combustion. (author)

  6. Atmospheric mercury in Changbai Mountain area, northeastern China II. The distribution of reactive gaseous mercury and particulate mercury and mercury deposition fluxes.

    Science.gov (United States)

    Wan, Qi; Feng, Xinbin; Lu, Julia; Zheng, Wei; Song, Xinjie; Li, Ping; Han, Shijie; Xu, Hao

    2009-08-01

    Reactive gaseous mercury (RGM) and particulate mercury (Hgp) concentrations in ambient air from a remote site at Changbai Mountain area in northeastern China were intermittently monitored from August 2005 to July 2006 totaling 93 days representing fall, winter-spring and summer season, respectively. Rainwater and snow samples were collected during a whole year, and total mercury (THg) in rain samples were used to calculate wet depositional flux. A throughfall method and a model method were used to estimate dry depositional flux. Results showed mean concentrations of RGM and Hgp are 65 and 77 pg m(-3). Compared to background concentrations of atmospheric mercury species in Northern Hemisphere, RGM and Hgp are significantly elevated in Changbai area. Large values for standard deviation indicated fast reactivity and a low residence time for these mercury species. Seasonal variability is also important, with lower mercury levels in summer compared to other seasons, which is attributed to scavenging by rainfall and low local mercury emissions in summer. THg concentrations ranged from 11.5 to 15.9 ng L(-1) in rainwater samples and 14.9-18.6 ng L(-1) in throughfall samples. Wet depositional flux in Changbai area is calculated to be 8.4 microg m(-2) a(-1), and dry deposition flux is estimated to be 16.5 microg m(-2) a(-1) according to a throughfall method and 20.2 microg m(-2) a(-1) using a model method.

  7. Energy transfer upon collision of selectively excited CO{sub 2} molecules: State-to-state cross sections and probabilities for modeling of atmospheres and gaseous flows

    Energy Technology Data Exchange (ETDEWEB)

    Lombardi, A., E-mail: ebiu2005@gmail.com; Faginas-Lago, N.; Pacifici, L.; Grossi, G. [Dipartimento di Chimica, Università di Perugia, via Elce di Sotto 8, 06123 Perugia (Italy)

    2015-07-21

    Carbon dioxide molecules can store and release tens of kcal/mol upon collisions, and such an energy transfer strongly influences the energy disposal and the chemical processes in gases under the extreme conditions typical of plasmas and hypersonic flows. Moreover, the energy transfer involving CO{sub 2} characterizes the global dynamics of the Earth-atmosphere system and the energy balance of other planetary atmospheres. Contemporary developments in kinetic modeling of gaseous mixtures are connected to progress in the description of the energy transfer, and, in particular, the attempts to include non-equilibrium effects require to consider state-specific energy exchanges. A systematic study of the state-to-state vibrational energy transfer in CO{sub 2} + CO{sub 2} collisions is the focus of the present work, aided by a theoretical and computational tool based on quasiclassical trajectory simulations and an accurate full-dimension model of the intermolecular interactions. In this model, the accuracy of the description of the intermolecular forces (that determine the probability of energy transfer in molecular collisions) is enhanced by explicit account of the specific effects of the distortion of the CO{sub 2} structure due to vibrations. Results show that these effects are important for the energy transfer probabilities. Moreover, the role of rotational and vibrational degrees of freedom is found to be dominant in the energy exchange, while the average contribution of translations, under the temperature and energy conditions considered, is negligible. Remarkable is the fact that the intramolecular energy transfer only involves stretching and bending, unless one of the colliding molecules has an initial symmetric stretching quantum number greater than a threshold value estimated to be equal to 7.

  8. Energy transfer upon collision of selectively excited CO2 molecules: State-to-state cross sections and probabilities for modeling of atmospheres and gaseous flows.

    Science.gov (United States)

    Lombardi, A; Faginas-Lago, N; Pacifici, L; Grossi, G

    2015-07-21

    Carbon dioxide molecules can store and release tens of kcal/mol upon collisions, and such an energy transfer strongly influences the energy disposal and the chemical processes in gases under the extreme conditions typical of plasmas and hypersonic flows. Moreover, the energy transfer involving CO2 characterizes the global dynamics of the Earth-atmosphere system and the energy balance of other planetary atmospheres. Contemporary developments in kinetic modeling of gaseous mixtures are connected to progress in the description of the energy transfer, and, in particular, the attempts to include non-equilibrium effects require to consider state-specific energy exchanges. A systematic study of the state-to-state vibrational energy transfer in CO2 + CO2 collisions is the focus of the present work, aided by a theoretical and computational tool based on quasiclassical trajectory simulations and an accurate full-dimension model of the intermolecular interactions. In this model, the accuracy of the description of the intermolecular forces (that determine the probability of energy transfer in molecular collisions) is enhanced by explicit account of the specific effects of the distortion of the CO2 structure due to vibrations. Results show that these effects are important for the energy transfer probabilities. Moreover, the role of rotational and vibrational degrees of freedom is found to be dominant in the energy exchange, while the average contribution of translations, under the temperature and energy conditions considered, is negligible. Remarkable is the fact that the intramolecular energy transfer only involves stretching and bending, unless one of the colliding molecules has an initial symmetric stretching quantum number greater than a threshold value estimated to be equal to 7.

  9. Detection of atmospheric gaseous amines and amides by a high-resolution time-of-flight chemical ionization mass spectrometer with protonated ethanol reagent ions

    Directory of Open Access Journals (Sweden)

    L. Yao

    2016-11-01

    Full Text Available Amines and amides are important atmospheric organic-nitrogen compounds but high time resolution, highly sensitive, and simultaneous ambient measurements of these species are rather sparse. Here, we present the development of a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS method, utilizing protonated ethanol as reagent ions to simultaneously detect atmospheric gaseous amines (C1 to C6 and amides (C1 to C6. This method possesses sensitivities of 5.6–19.4 Hz pptv−1 for amines and 3.8–38.0 Hz pptv−1 for amides under total reagent ion signals of  ∼  0.32 MHz. Meanwhile, the detection limits were 0.10–0.50 pptv for amines and 0.29–1.95 pptv for amides at 3σ of the background signal for a 1 min integration time. Controlled characterization in the laboratory indicates that relative humidity has significant influences on the detection of amines and amides, whereas the presence of organics has no obvious effects. Ambient measurements of amines and amides utilizing this method were conducted from 25 July to 25 August 2015 in urban Shanghai, China. While the concentrations of amines ranged from a few parts per trillion by volume to hundreds of parts per trillion by volume, concentrations of amides varied from tens of parts per trillion by volume to a few parts per billion by volume. Among the C1- to C6-amines, the C2-amines were the dominant species with concentrations up to 130 pptv. For amides, the C3-amides (up to 8.7 ppb were the most abundant species. The diurnal and backward trajectory analysis profiles of amides suggest that in addition to the secondary formation of amides in the atmosphere, industrial emissions could be important sources of amides in urban Shanghai. During the campaign, photo-oxidation of amines and amides might be a main loss pathway for them in daytime, and wet deposition was also an important sink.

  10. Gaseous emissions from coal stockpiles

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-01-15

    Stockpiled coal undergoes atmospheric oxidation and desorption processes during open air storage. These processes release gases to the environment which may effect health and safety by their toxicity and flammability. In extreme cases, this could lead to a fire. This report discusses gaseous emissions from coal stockpiles. It covers gas emission mechanisms, and gas sampling and testing methods, before examining in more detail the principal gases that have been emitted. It concludes that there is limited research in this area and more data are needed to evaluate the risks of gaseous emissions. Some methods used to prevent coal self-heating and spontaneous combustion can be applied to reduce emissions from coal stockpiles.

  11. Monsoon-driven transport of atmospheric mercury to the South China Sea from the Chinese mainland and Southeast Asia-Observation of gaseous elemental mercury at a background station in South China.

    Science.gov (United States)

    Liu, Ming; Chen, Laiguo; Xie, Donghai; Sun, Jiaren; He, Qiusheng; Cai, Limei; Gao, Zhiqiang; Zhang, Yiqiang

    2016-11-01

    Concentrations of gaseous elemental mercury (GEM) were continuously monitored from May 2011 to May 2012 at the Wuzhishan State Atmosphere Background Monitoring Station (109°29'30.2″ E, 18°50'11.0″ N) located in Hainan Island. This station is an ideal site for monitoring long-range transport of atmospheric pollutants from mainland China and Southeast Asia to South China Sea. Annual average GEM concentration was 1.58 ± 0.71 ng m -3 during the monitoring period, which was close to background values in the Northern Hemisphere. GEM concentrations showed a clear seasonal variation with relatively higher levels in autumn (1.86 ± 0.55 ng m -3 ) and winter (1.80 ± 0.62 ng m -3 ) and lower levels in spring (1.16 ± 0.45 ng m -3 ) and summer (1.43 ± 0.46 ng m -3 ). Long-range atmospheric transport dominated by monsoons was a dominant factor influencing the seasonal variations of GEM. The GEM diel trends were related to the wind speed and long-range atmospheric mercury transport. We observed 30 pollution episodes throughout the monitoring period. The analysis of wind direction and backward trajectory suggested that elevated GEM concentrations at the monitoring site were primarily related to the outflows of atmospheric Hg from mainland China and the Indochina peninsula. The △GEM/△CO values also suggested that GEM was significantly affected by the long-range transport from the anthropogenic sources and biomass burning in Asia and Indochina peninsula.

  12. A Population Study of Gaseous Exoplanets

    Science.gov (United States)

    Tsiaras, A.; Waldmann, I. P.; Zingales, T.; Rocchetto, M.; Morello, G.; Damiano, M.; Karpouzas, K.; Tinetti, G.; McKemmish, L. K.; Tennyson, J.; Yurchenko, S. N.

    2018-04-01

    We present here the analysis of 30 gaseous extrasolar planets, with temperatures between 600 and 2400 K and radii between 0.35 and 1.9 R Jup. The quality of the HST/WFC3 spatially scanned data combined with our specialized analysis tools allow us to study the largest and most self-consistent sample of exoplanetary transmission spectra to date and examine the collective behavior of warm and hot gaseous planets rather than isolated case studies. We define a new metric, the Atmospheric Detectability Index (ADI) to evaluate the statistical significance of an atmospheric detection and find statistically significant atmospheres in around 16 planets out of the 30 analyzed. For most of the Jupiters in our sample, we find the detectability of their atmospheres to be dependent on the planetary radius but not on the planetary mass. This indicates that planetary gravity plays a secondary role in the state of gaseous planetary atmospheres. We detect the presence of water vapour in all of the statistically detectable atmospheres, and we cannot rule out its presence in the atmospheres of the others. In addition, TiO and/or VO signatures are detected with 4σ confidence in WASP-76 b, and they are most likely present in WASP-121 b. We find no correlation between expected signal-to-noise and atmospheric detectability for most targets. This has important implications for future large-scale surveys.

  13. Formation of high-molecular-weight compounds via the heterogeneous reactions of gaseous C8-C10 n-aldehydes in the presence of atmospheric aerosol components

    Science.gov (United States)

    Han, Yuemei; Kawamura, Kimitaka; Chen, Qingcai; Mochida, Michihiro

    2016-02-01

    A laboratory study on the heterogeneous reactions of straight-chain aldehydes was performed by exposing n-octanal, nonanal, and decanal vapors to ambient aerosol particles. The aerosol and blank filters were extracted using methanol. The extracts were nebulized and the resulting compositions were examined using a high-resolution time-of-flight aerosol mass spectrometer. The mass spectral analysis showed that the exposures of the aldehydes to aerosol samples increased the peak intensities in the high mass range. The peaks in the mass spectra of the aerosol samples after exposure to different aldehydes were characterized by a homologous series of peak shifts due to the addition of multiple CH2 units. This result is explained by the formation of high-molecular-weight (HMW) compounds that contain single or multiple aldehyde moieties. The HMW fragment peaks for the blank filters exposed to n-aldehydes were relatively weak, indicating an important contribution from the ambient aerosol components to the formation of the HMW compounds. Among the factors affecting the overall interaction of aldehydes with atmospheric aerosol components, gas phase diffusion possibly limited the reactions under the studied conditions; therefore, their occurrence to a similar degree in the atmosphere is not ruled out, at least for the reactions involving n-nonanal and decanal. The major formation pathways for the observed HMW products may be the self-reactions of n-aldehydes mediated by atmospheric aerosol components and the reactions of n-aldehydes with organic aerosol components. The observed formation of HMW compounds encourages further investigations into their effects on the aerosol properties as well as the organic aerosol mass in the atmosphere.

  14. Gaseous poison injection device

    International Nuclear Information System (INIS)

    Kubota, Ryuji; Sugisaki, Toshihiko; Inada, Ikuo.

    1983-01-01

    Purpose: To rapidly control the chain reaction due to thermal neutrons in a reactor core by using gaseous poisons as back-up means for control rod drives. Constitution: Gaseous poisons having a large neutron absorption cross section are used as back-up means for control rod drives. Upon failure of control rod insertion, the gaseous poisons are injected into the lower portion of the reactor core to control the reactor power. As the gaseous poisons, vapors at a high temperature and a higher pressure than that of the coolants in the reactor core are injected to control the reactor power due to the void effects. Since the gaseous poisons thus employed rapidly reach the reactor core and form gas bubbles therein, the deccelerating effect of the thermal neutrons is decreased to reduce the chain reaction. (Moriyama, K.)

  15. Development of gaseous photomultiplier

    International Nuclear Information System (INIS)

    Tokanai, F.; Sumiyoshi, T.; Sugiyama, H.; Okada, T.

    2014-01-01

    We have been developing gaseous photomultiplier tubes (PMTs) with alkali photocathode combined with micropattern gas detectors (MPGDs). The potential advantage of the gaseous PMT is that it can achieve a very large effective area with adequate position and timing resolutions. In addition, it will be easily operated under a very high magnetic field, compared with the conventional vacuum-based PMT. To evaluate the gaseous PMTs filled with Ne and Ar based gas mixture, we have developed gaseous PMTs with an alkali photocathode combined with MPGDs such as a glass capillary plate, GEM, and Micromegas detector. We describe the recent development of the gaseous PMTs, particularly the production of the photocathode, gas gain, ion and photon feedbacks, quantum efficiency, and the characteristics in the magnetic field environment. (author)

  16. Air pollution with gaseous emissions and methods for their removal

    International Nuclear Information System (INIS)

    Vassilev, Venceslav; Boycheva, Sylvia; Fidancevska, Emilija

    2009-01-01

    Information concerning gaseous pollutants generated in the atmosphere, as a result of fuel incineration processes in thermal power and industrial plants, was summarized. The main methods and technologies for flue gases purification from the most ecologically hazardous pollutants are comparatively discussed. Keywords: gaseous pollutants, aerosols, flue gas purification systems and technologies, air ecology control

  17. Proposition of resolution aiming at the creation of an inquiry commission on the gaseous releases and/or liquid in atmosphere following the incident on the site of the Tricastin; Proposition de resolution visant a la creation d'une commission d'enquete sur les rejets gazeux et/ou liquides dans l'atmosphere suite a l'incident sur le site du Tricastin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    After the Tricastin incident occurred in july 2008 a proposition of resolution has been presented at the National Assembly. This commission will be the occasion to review the procedure to be adopted by authorities during gaseous releases in the atmosphere. It will be also the occasion to check the situation of ground water (water table) located near the french nuclear power plants. (N.C.)

  18. Atmospheric chemistry and climate

    OpenAIRE

    Satheesh, SK

    2012-01-01

    Atmospheric chemistry is a branch of atmospheric science where major focus is the composition of the Earth's atmosphere. Knowledge of atmospheric composition is essential due to its interaction with (solar and terrestrial) radiation and interactions of atmospheric species (gaseous and particulate matter) with living organisms. Since atmospheric chemistry covers a vast range of topics, in this article the focus is on the chemistry of atmospheric aerosols with special emphasis on the Indian reg...

  19. Gaseous waste processing facility

    International Nuclear Information System (INIS)

    Konno, Masanobu; Uchiyama, Yoshio; Suzuki, Kunihiko; Kimura, Masahiro; Kawabe, Ken-ichi.

    1992-01-01

    Gaseous waste recombiners 'A' and 'B' are connected in series and three-way valves are disposed at the upstream and the downstream of the recombiners A and B, and bypass lines are disposed to the recombiners A and B, respectively. An opening/closing controller for the three-way valves is interlocked with a hydrogen densitometer disposed to a hydrogen injection line. Hydrogen gas and oxygen gas generated by radiolysis in the reactor are extracted from a main condenser and caused to flow into a gaseous waste processing system. Gaseous wastes are introduced together with overheated steams to the recombiner A upon injection of hydrogen. Both of the bypass lines of the recombiners A and B are closed, and recombining reaction for the increased hydrogen gas is processed by the recombiners A and B connected in series. In an operation mode not conducting hydrogen injection, it is passed through the bypass line of the recombiner A and processed by the recombiner B. With such procedures, the increase of gaseous wastes due to hydrogen injection can be coped with existent facilities. (I.N.)

  20. Absorbing method of iodine in radioactive gaseous wastes

    International Nuclear Information System (INIS)

    Fukutome, Yutaka; Mifuji, Hiroshi; Ito, Sakae.

    1983-01-01

    Purpose: To maintain an iodine adsorbing efficiency at a high level by keeping the adsorbing atmosphere to more than a predetermined temperature to thereby suppress the degradation and the activity reduction in zeolite. Method: Adsorption and desorption-regeneration of gaseous wastes are performed in parallel by heating gaseous wastes in a heater and switchingly supplying the same to adsorption columns by way of valve operation. Processed gases are cooled in a cooler and desorbed gases are supplied to an after-treatment device to eliminate or recover iodine 131. In the adsorption column, iodine in gaseous wastes is adsorbed to remove by using zeolite, wherein the adsorbing atmosphere is kept at a temperature higher than 40 0 C. This can prevent the formation of an aqueous HNO 3 solution from NO 2 and H 2 O contained in the gaseous wastes and prevent the degradation of the zeolite adsorption layer. (Kawakami, Y.)

  1. Attachment of gaseous fission products to aerosols

    International Nuclear Information System (INIS)

    Skyrme, G.

    1985-01-01

    Accidents may occur in which the integrity of fuel cladding is breached and volatile fission products are released to the containment atmosphere. In order to assess the magnitude of the subsequent radiological hazard it is necessary to know the transport behaviour of such fission products. It is frequently assumed that the fission products remain in the gaseous phase. There is a possibility, however, that they may attach themselves to particles and hence substantially modify their transport properties. This paper provides a theoretical assessment of the conditions under which gaseous fission products may be attached to aerosol particles. Specific topics discussed are: the mass transfer of a gaseous fission product to an isolated aerosol particle in an infinite medium; the rate at which the concentration of fission products in the gas phase diminishes within a container as a result of deposition on a population of particles; and the distribution of deposited fission product between different particle sizes in a log-normal distribution. It is shown that, for a given mass, small particles are more efficient for fission product attachment, and that only small concentrations of such particles may be necessary to achieve rapid attachment. Conditions under which gaseous fission products are not attached to particles are also considered, viz, the competing processes of deposition onto the containment walls and onto aerosol particles, and the possibility of the removal of aerosols from the containment by various deposition processes, or agglomeration, before attachment takes place. (author)

  2. Gaseous diffusion system

    International Nuclear Information System (INIS)

    Garrett, G.A.; Shacter, J.

    1978-01-01

    A gaseous diffusion system is described comprising a plurality of diffusers connected in cascade to form a series of stages, each of the diffusers having a porous partition dividing it into a high pressure chamber and a low pressure chamber, and means for combining a portion of the enriched gas from a succeeding stage with a portion of the enriched gas from the low pressure chamber of each stage and feeding it into one extremity of the high pressure chamber thereof

  3. Transporte de oócitos bovinos em meio de maturação sem controle de atmosfera gasosa Transport of bovine oocytes in maturation medium without a controlled gaseous atmosphere

    Directory of Open Access Journals (Sweden)

    Fábio Gallas Leivas

    2004-02-01

    aspirated from 2 to 8mm follicles obtained from bovine slaughterhouse ovaries (11 replications were randomly distributed in four treatments. Oocytes were matured for 24h with modified TCM-199 Earle salts, plus 25mM bicarbonate, 25 mM HEPES, rFSH-h, Estrus Cow Serum (ECS, and piruvate at 39ºC, in incubator with 5% CO2 and saturated humidity (Control Group, n=296 or exposed to a simulated transport for 6 (T6, n=286, 12 (T12, n=294 or 18h (T18, n=301 in maturation medium containing TCM + HEPES, in a 39ºC water bath, with the same components used in the Control Group, but with 1mM bicarbonate. At the conclusion of each transport period, oocytes were transferred to dishes with maturation medium to reach 24h in incubator, under the same conditions described for the Control group. Fertilization was accomplished during 18h, with the same temperature and gaseous atmosphere, in FERT-TALP plus heparin. The insemination dose was 1x106 spermatozoa/mL, sorted by swim-up. Presumptive zygotes were cultured in SOF medium + 5% ECS for 8 days, in incubator at 39ºC using gasified bags with 5% CO2, 5% O2 and 90% N2. Cleavage rates did not differ between treatments. Embryonic development rates at D7 were similar for Control (20.9%, T6 (19.2% and T12 (21.4% groups, with a reduction (P0.05 in hatched blastocyst rate. The average number of cells of hatched blastocysts was similar (P>0.05 in Control (136, T6 (125.5 and T12 (126.8 groups. These results indicate the possibility of transporting bovine oocytes in maturation medium containing TCM + HEPES, without controlled gaseous atmosphere environment, at 39ºC, for up to 12 hours. This technique offers a practical and efficient alternative for the transport of bovine oocytes for in vitro production of bovine embryos (IVP.

  4. Two new sources of reactive gaseous mercury in the free troposphere

    OpenAIRE

    H. Timonen; J. L. Ambrose; D. A. Jaffe

    2012-01-01

    Mercury (Hg) is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM) generates reactive gaseous mercury (RGM) which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the sources and chemical ...

  5. Retention of gaseous isotopes

    International Nuclear Information System (INIS)

    Yarbro, O.O.; Mailen, J.C.; Stephenson, M.J.

    1977-01-01

    Retention of gaseous fission products during fuel reprocessing has, in the past, been limited to a modest retention of 131 I when processing fuels decayed less than about 180 days. The projected rapid growth of the nuclear power industry along with a desire to minimize environmental effects is leading to the reassessment of requirements for retention of gaseous fission products, including 131 I, 129 I, 85 Kr, 3 H, and 14 C. Starting in the late 1960s, a significant part of the LMFBR reprocessing development program has been devoted to understanding the behavior of gaseous fission products in plant process and effluent streams and the development of advanced systems for their removal. Systems for iodine control include methods for evolving up to 99% of the iodine from dissolver solutions to minimize its introduction and distribution throughout downstream equipment. An aqueous scrubbing system (Iodox) using 20 M HNO 3 as the scrubbing media effectively removes all significant iodine forms from off-gas streams while handling the kilogram quantities of iodine present in head-end and dissolver off-gas streams. Silver zeolite is very effective for removing iodine forms at low concentration from the larger-volume plant off-gas streams. Removal of iodine from plant liquid effluents by solid sorbents either prior to or following final vaporization appears feasible. Krypton is effectively released during dissolution and can be removed from the relatively small volume head-end and dissolver off-gas stream. Two methods appear applicable for removal and concentration of krypton: (1) selective absorption in fluorocarbons, and (2) cryogenic absorption in liquid nitrogen. The fluorocarbon absorption process appears to be rather tolerant of the normal contaminants (H 2 O, CO 2 , NOsub(x), and organics) present in typical reprocessing plant off-gas whereas the cryogenic system requires an extensive feed gas pretreatment system. Retention of tritium in a reprocessing plant is

  6. Gossip: Gaseous pixels

    Science.gov (United States)

    Koffeman, E. N.

    2007-12-01

    Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a 55Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated.

  7. Gossip: Gaseous pixels

    Energy Technology Data Exchange (ETDEWEB)

    Koffeman, E.N. [Nikhef, Kruislaan 409, 1098 SJ Amsterdam (Netherlands)], E-mail: d77@nikhef.nl

    2007-12-01

    Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a {sup 55}Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated.

  8. Gossip: Gaseous pixels

    International Nuclear Information System (INIS)

    Koffeman, E.N.

    2007-01-01

    Several years ago a revolutionary miniature TPC was developed using a pixel chip with a Micromegas foil spanned over it. To overcome the mechanical stability problems and improve the positioning accuracy while spanning a foil on top of a small readout chip a process has been developed in which a Micromegas-like grid is applied on a CMOS wafer in a post-processing step. This aluminum grid is supported on insulating pillars that are created by etching after the grid has been made. The energy resolution (measured on the absorption of the X-rays from a 55 Fe source) was remarkably good. Several geometries have since been tested and we now believe that a Gas On Slimmed Silicon Pixel chip' (Gossip) may be realized. The drift region of such a gaseous pixel detector would be reduced to a millimeter. Such a detector is potentially very radiation hard (SLHC vertexing) but aging and sparking must be eliminated

  9. Hydrogenating gaseous hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Nicolardot, P L.F.

    1930-08-06

    Gaseous hydrocarbons obtained by the destructive distillation of carbonaceous materials are simultaneously desulfurized and hydrogenated by passing them at 350 to 500/sup 0/C, mixed with carbon monoxide and water vapor over lime mixed with metallic oxides present in sufficient amount to absorb the carbon dioxide as it is formed. Oxides of iron, copper, silver, cobalt, and metals of the rare earths may be used and are mixed with the lime to form a filling material of small pieces filling the reaction vessel which may have walls metallized with copper and zinc dust. The products are condensed and fixed with absorbents, e.g. oils, activated carbon, silica gels. The metallic masses may be regenerated by a hot air stream and by heating in inert gases.

  10. Transfer of gaseous iodine to Tradescantia

    International Nuclear Information System (INIS)

    Nakamura, Yuji; Ohmomo, Yoichiro.

    1984-01-01

    Transfer rates of gaseous elemental iodine and methyliodide from atmosphere to Tradescantia were investigated in relation to supposed genetic mutation due to radioactive iodine released from nuclear facilities. The estimated transfer rate of elemental iodine to the young buds of Tradescantia, which was given as the ratio of iodine uptake rate per unit weight of the plant to the concentration of the element in the air, was approximately 7 x 10 -2 cm 3 /g.sec, about 30 to 40 times higher than that of methyliodide. The contribution of direct deposition of elemental iodine was suggested to be significant, although methyliodide was mainly absorbed by respiration through stomata of the plant. (author)

  11. Emission of gaseous organic pollutants and flue gas treatment technology

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Sun, Y.

    2007-01-01

    Gaseous organic pollutants are emitted into atmosphere from various sources, creating a threat to the environment and man. New, economical technologies are needed for flue gas treatment. Emission sources of pollutants are reviewed and different treatment technologies are discussed in this report. (authors)

  12. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  13. Controlled Atmosphere Stunning

    NARCIS (Netherlands)

    Lambooij, E.; Gerritzen, M.A.

    2009-01-01

    Controlled atmosphere (CAS) stunning includes several variations of gaseous mixtures given to induce an anaesthetic state before slaughter poultry. One method of multi phase CAS is to unload the birds out of the crate on a conveyor belt and subject the birds to an atmosphere of 30% O2, 40% CO2 and

  14. Gaseous waste processing device

    International Nuclear Information System (INIS)

    Kubokoya, Takashi.

    1992-01-01

    In a gaseous waste processing device, if activated carbon is charged uniformly to a holdup tower, the amount of radioactive rare gases held in a first tower at the uppermost stream is increased to greater than that in other towers at the downstream since the radioactive rare gases decay in the form of an exponential function. Then in the present invention, the entire length of a plurality of activated carbon holdup towers connected in series is made longer than that of the towers in the downstream. As a result, since the amount of radioactive rare gases held in each of the holdup towers is made uniform, even if any one of connecting pipelines is ruptured, the amount of radioactive rare gases flown out is uniform. Only the body length of the holdup tower is changed because it is economical in view of the design and the manufacture of the vessel, and the cross section of the portion in which activated carbons are filled is made identical to keep the optimum flow rate of the rare gases. Thus, the radioactivity releasing amount can be minimized upon occurrence of an accident. (N.H.)

  15. Gaseous radioactive waste processing system

    International Nuclear Information System (INIS)

    Onizawa, Hideo.

    1976-01-01

    Object: To prevent explosion of hydrogen gas within gaseous radioactive waste by removing the hydrogen gas by means of a hydrogen absorber. Structure: A coolant extracted from a reactor cooling system is sprayed by nozzle into a gaseous phase (hydrogen) portion within a tank, thus causing slipping of radioactive rare gas. The gaseous radioactive waste rich in hydrogen, which is purged in the tank, is forced by a waste gas compressor into a hydrogen occlusion device. The hydrogen occlusion device is filled with hydrogen occluding agents such as Mg, Mg-Ni alloy, V-Nb alloy, La-Ni alloy and so forth, and hydrogen in the waste gas is removed through reaction to produce hydrogen metal. The gaseous radioactive waste, which is deprived of hydrogen and reduced in volume, is stored in an attenuation tank. The hydrogen stored in the hydrogen absorber is released and used again as purge gas. (Horiuchi, T.)

  16. Dielectrophoretic separation of gaseous isotopes

    International Nuclear Information System (INIS)

    McConnell, D.B.

    1976-01-01

    This invention relates to a process for the separation of gaseous isotopes by electrophoresis assisted by convective countercurrent flow and to an apparatus for use in the process. The invention is especially applicable to heavy water separation from steam; however, it is to be understood that the invention is broadly applicable to the separation of gaseous isotopes having different dipole moments and/or different molecular weights. (author)

  17. Low energy consumption method for separating gaseous mixtures and in particular for medium purity oxygen production

    Science.gov (United States)

    Jujasz, Albert J.; Burkhart, James A.; Greenberg, Ralph

    1988-01-01

    A method for the separation of gaseous mixtures such as air and for producing medium purity oxygen, comprising compressing the gaseous mixture in a first compressor to about 3.9-4.1 atmospheres pressure, passing said compressed gaseous mixture in heat exchange relationship with sub-ambient temperature gaseous nitrogen, dividing the cooled, pressurized gaseous mixture into first and second streams, introducing the first stream into the high pressure chamber of a double rectification column, separating the gaseous mixture in the rectification column into a liquid oxygen-enriched stream and a gaseous nitrogen stream and supplying the gaseous nitrogen stream for cooling the compressed gaseous mixture, removing the liquid oxygen-enriched stream from the low pressure chamber of the rectification column and pumping the liquid, oxygen-enriched steam to a predetermined pressure, cooling the second stream, condensing the cooled second stream and evaporating the oxygen-enriched stream in an evaporator-condenser, delivering the condensed second stream to the high pressure chamber of the rectification column, and heating the oxygen-enriched stream and blending the oxygen-enriched stream with a compressed blend-air stream to the desired oxygen concentration.

  18. Treatment of Radioactive Gaseous Waste

    International Nuclear Information System (INIS)

    2014-07-01

    Radioactive waste, with widely varying characteristics, is generated from the operation and maintenance of nuclear power plants, nuclear fuel cycle facilities, research laboratories and medical facilities. The waste needs to be treated and conditioned as necessary to provide waste forms acceptable for safe storage and disposal. Although radioactive gaseous radioactive waste does not constitute the main waste flow stream at nuclear fuel cycle and radioactive waste processing facilities, it represents a major source for potential direct environmental impact. Effective control and management of gaseous waste in both normal and accidental conditions is therefore one of the main issues of nuclear fuel cycle and waste processing facility design and operation. One of the duties of an operator is to take measures to avoid or to optimize the generation and management of radioactive waste to minimize the overall environmental impact. This includes ensuring that gaseous and liquid radioactive releases to the environment are within authorized limits, and that doses to the public and the effects on the environment are reduced to levels that are as low as reasonably achievable. Responsibilities of the regulatory body include the removal of radioactive materials within authorized practices from any further regulatory control — known as clearance — and the control of discharges — releases of gaseous radioactive material that originate from regulated nuclear facilities during normal operation to the environment within authorized limits. These issues, and others, are addressed in IAEA Safety Standards Series Nos RS-G-1.7, WS-G-2.3 and NS-G-3.2. Special systems should be designed and constructed to ensure proper isolation of areas within nuclear facilities that contain gaseous radioactive substances. Such systems consist of two basic subsystems. The first subsystem is for the supply of clean air to the facility, and the second subsystem is for the collection, cleanup and

  19. Dielectrophoretic separation of gaseous isotopes

    International Nuclear Information System (INIS)

    McConnell, D.B.

    1975-01-01

    Gaseous isotopes are separated from a mixture in a vertically elongated chamber by subjecting the mixture to a nonuniform transverse electric field. Dielectrophoretic separation of the isotopes is effected, producing a transverse temperature gradient in the chamber, thereby enhancing the separation by convective countercurrent flow. In the example given, the process and apparatus are applied to the production of heavy water from steam

  20. Stress corrosion in gaseous environment

    International Nuclear Information System (INIS)

    Miannay, Dominique.

    1980-06-01

    The combined influences of a stress and a gaseous environment on materials can lead to brittleness and to unexpected delayed failure by stress corrosion cracking, fatigue cracking and creep. The most important parameters affering the material, the environment, the chemical reaction and the stress are emphasized and experimental works are described. Some trends for further research are given [fr

  1. Microbial production of gaseous hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Hideo

    1987-10-20

    Microbial production of ethylene, isobutane and a saturated gaseous hydrocarbon mixture was described. Microbial ethylene production was studied with Penicillium digitatum IFO 9372 and a novel pathway of the ethylene biosynthesis through alpha-ketoglutarate was proposed. Rhodotorula minuta IFO 1102 was selected for the microbial production of isobutane and the interesting actions of L-leucine and L-phenylalanine for the isobutane production were found. It was finally presented about the microbial production of a saturated gaseous hydrocarbon mixture with Rhizopus japonicus IFO 4758 was described. A gas mixture was produced through a chemical reaction of SH compounds and some cellular component such as squalene under aerobic conditions. (4 figs, 7 tabs, 41 refs)

  2. Electron beam gaseous pollutants treatment

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    1999-01-01

    Emission of gaseous pollutants, mostly during combustion of fossil fuels, creates a threat to the environment. New, economical technologies are needed for flue gas treatment. A physico-chemical basis of the process using electron beam for the simultaneous removal of sulfur and nitrogen oxides and volatile organic compounds are presented in this report. Development of the process and its upscaling has been discussed. (author)

  3. Release of gaseous tritium during reprocessing

    International Nuclear Information System (INIS)

    Bruecher, H.; Hartmann, K.

    1983-01-01

    About 50% of the tritium put through an LWR reprocessing plant is obtained as tritium-bearing water, HTO. Gaseous tritium, HT has a radiotoxicity which is by 4 orders of magnitude lower than that of HTO. A possibility for the removal of HTO could therefore be its conversion into the gas phase with subsequent emission of the HT into the atmosphere. However, model computations which are, in part, supported by experimental data reveal that the radiation exposure caused by HT release is only by about one order of magnitude below that caused by HTO. This is being attributed to the relatively quick reoxidation of HT by soil bacteria. Two alternatives for producing HT from HTO (electrolysis; voloxidation with subsequent electrolysis) are presented and compared with the reference process of deep-well injection of HTO. The authors come to the conclusion that tritium removal by HT release into the atmosphere cannot be recommended at present under either radiological or economic aspects. (orig.) [de

  4. Generation of gaseous tritium standards

    International Nuclear Information System (INIS)

    Hohorst, F.A.

    1994-09-01

    The determination of aqueous and non-aqueous tritium in gaseous samples is one type of determination often requested of radioanalytical laboratories. This determination can be made by introducing the sample as a gas into a sampling train containing two silica gel beds separated by.a catalytic oxidizer bed. The first bed traps tritiated water. The sample then passes into and through the oxidizer bed where non-aqueous tritium containing species are oxidized to water and other products of combustion. The second silica gel bed then traps the newly formed tritiated water. Subsequently, silica gel is removed to plastic bottles, deionized water is added, and the mixture is permitted to equilibrate. The tritium content of the equilibrium mixture is then determined by conventional liquid scintillation counting (LSC). For many years, the moisture content of inert, gaseous samples has been determined using monitors which quantitatively electrolyze the moisture present after that moisture has been absorbed by phosphorous pentoxide or other absorbents. The electrochemical reaction is quantitative and definitive, and the energy consumed during electrolysis forms the basis of the continuous display of the moisture present. This report discusses the experimental evaluation of such a monitor as the basis for a technique for conversion of small quantities of SRMs of tritiated water ( 3 HOH) into gaseous tritium standards ( 3 HH)

  5. Gaseous diffusion -- the enrichment workhorse

    International Nuclear Information System (INIS)

    Shoemaker, J.E. Jr.

    1984-01-01

    Construction of the first large-scale gaseous diffusion facility was started as part of the Manhattan Project in Oak Ridge, Tennessee, in 1943. This facility, code named ''K-25,'' began operation in January 1945 and was fully on stream by September 1945. Four additional process buildings were later added in Oak Ridge as the demand for enriched uranium escalated. New gaseous diffusion plants were constructed at Paducah, Kentucky, and Portsmouth, Ohio, during this period. The three gaseous diffusion plants were the ''workhorses'' which provided the entire enriched uranium demand for the United States during the 1950s and 1960s. As the demand for enriched uranium for military purposes decreased during the early 1960s, power to the diffusion plants was curtailed to reduce production. During the 1960s, as plans for the nuclear power industry were formulated, the role of the diffusion plants gradually changed from providing highly-enriched uranium for the military to providing low-enriched uranium for power reactors

  6. Experiments for detection of gaseous Po-210 originated from microbial activity in the environment

    International Nuclear Information System (INIS)

    Ishimoto, A.; Momoshima, N.

    2006-01-01

    We attempted to detect gaseous Po-210 (half-life 138d) emitted from organisms in the environment. Gaseous Po-210 was tried to collect in 0.5 M nitric acid solution after passing the atmospheric air through filters and a distilled water bubbler, which would remove aerosols existing in the air. The activity of Po-210 was determined by alpha spectrometry after radiochemical separation and electrolytic deposition of Po-210 on a silver disk. Twenty seven point four mBq of Po-210 was observed when 800 m 3 atmospheric air was sampled. Blank of Po-210 in regents and the sampling system was 4.9-6.8 mBq. The concentration of Po-210 observed in the atmospheric air was, thus about 5 times higher than the background; the results strongly support existence of gaseous Po-210 in the environment. (author)

  7. Radiolytical oxidation of gaseous iodine by beta radiation

    International Nuclear Information System (INIS)

    Kaerkelae, Teemu; Auvinen, Ari; Kekki, Tommi; Kotiluoto, Petri; Lyyraenen, Jussi; Jokiniemi, Jorma

    2015-01-01

    Iodine is one of the most radiotoxic fission product released from fuel during a severe nuclear power plant accident. Within the containment building, iodine compounds can react e.g. on the painted surfaces and form gaseous organic iodides. In this study, it was found out that gaseous methyl iodide (CH 3 I) is oxidised when exposed to beta radiation in an oxygen containing atmosphere. As a result, nucleation of aerosol particles takes place and the formation of iodine oxide particles is suggested. These particles are highly hygroscopic. They take up water from the air humidity and iodine oxides dissolve within the droplets. In order to mitigate the possible source term, it is of interest to understand the effect of beta radiation on the speciation of iodine.

  8. Radiolytical oxidation of gaseous iodine by beta radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kaerkelae, Teemu; Auvinen, Ari; Kekki, Tommi; Kotiluoto, Petri; Lyyraenen, Jussi [VTT Technical Research Centre of Finland, Espoo (Finland); Jokiniemi, Jorma [VTT Technical Research Centre of Finland, Espoo (Finland); Eastern Finland Univ., Kuopio (Finland)

    2015-07-01

    Iodine is one of the most radiotoxic fission product released from fuel during a severe nuclear power plant accident. Within the containment building, iodine compounds can react e.g. on the painted surfaces and form gaseous organic iodides. In this study, it was found out that gaseous methyl iodide (CH{sub 3}I) is oxidised when exposed to beta radiation in an oxygen containing atmosphere. As a result, nucleation of aerosol particles takes place and the formation of iodine oxide particles is suggested. These particles are highly hygroscopic. They take up water from the air humidity and iodine oxides dissolve within the droplets. In order to mitigate the possible source term, it is of interest to understand the effect of beta radiation on the speciation of iodine.

  9. Shuttle Gaseous Hydrogen Venting Risk from Flow Control Valve Failure

    Science.gov (United States)

    Drummond, J. Philip; Baurle, Robert A.; Gafney, Richard L.; Norris, Andrew T.; Pellett, Gerald L.; Rock, Kenneth E.

    2009-01-01

    This paper describes a series of studies to assess the potential risk associated with the failure of one of three gaseous hydrogen flow control valves in the orbiter's main propulsion system during the launch of Shuttle Endeavour (STS-126) in November 2008. The studies focused on critical issues associated with the possibility of combustion resulting from release of gaseous hydrogen from the external tank into the atmosphere during assent. The Shuttle Program currently assumes hydrogen venting from the external tank will result in a critical failure. The current effort was conducted to increase understanding of the risk associated with venting hydrogen given the flow control valve failure scenarios being considered in the Integrated In-Flight Anomaly Investigation being conducted by NASA.

  10. Gaseous Electron Multiplier (GEM) Detectors

    Science.gov (United States)

    Gnanvo, Kondo

    2017-09-01

    Gaseous detectors have played a pivotal role as tracking devices in the field of particle physics experiments for the last fifty years. Recent advances in photolithography and micro processing techniques have enabled the transition from Multi Wire Proportional Chambers (MWPCs) and Drift Chambers to a new family of gaseous detectors refer to as Micro Pattern Gaseous Detectors (MPGDs). MPGDs combine the basic gas amplification principle with micro-structure printed circuits to provide detectors with excellent spatial and time resolution, high rate capability, low material budget and high radiation tolerance. Gas Electron Multiplier (GEMs) is a well-established MPGD technology invented by F. Sauli at CERN in 1997 and deployed various high energy physics (HEP) and nuclear NP experiment for tracking systems of current and future NP experiments. GEM detector combines an exceptional high rate capability (1 MHz / mm2) and robustness against harsh radiation environment with excellent position and timing resolution performances. Recent breakthroughs over the past decade have allowed the possibility for large area GEMs, making them cost effective and high-performance detector candidates to play pivotal role in current and future particle physics experiments. After a brief introduction of the basic principle of GEM technology, I will give a brief overview of the GEM detectors used in particle physics experiments over the past decades and especially in the NP community at Thomas Jefferson National Laboratory (JLab) and Brookhaven National Laboratory (BNL). I will follow by a review of state of the art of the new GEM development for the next generation of colliders such as Electron Ion Collider (EIC) or High Luminosity LHC and future Nuclear Physics experiments. I will conclude with a presentation of the CERN-based RD51 collaboration established in 2008 and its major achievements regarding technological developments and applications of MPGDs.

  11. Hydrogen and Gaseous Fuel Safety and Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Lee C. Cadwallader; J. Sephen Herring

    2007-06-01

    Non-traditional motor fuels are receiving increased attention and use. This paper examines the safety of three alternative gaseous fuels plus gasoline and the advantages and disadvantages of each. The gaseous fuels are hydrogen, methane (natural gas), and propane. Qualitatively, the overall risks of the four fuels should be close. Gasoline is the most toxic. For small leaks, hydrogen has the highest ignition probability and the gaseous fuels have the highest risk of a burning jet or cloud.

  12. Radioactive gaseous waste processing device

    International Nuclear Information System (INIS)

    Kishi, Tadao.

    1990-01-01

    The present invention concerns a radioactive gaseous waste processing device used in BWR power plants. A heater is disposed to the lower portion of a dryer for dehydrating radioactive off gases. Further, a thermometer is disposed to a coolant return pipeway on the exit side of the cooling portion of the dryer and signals sent from the thermometer are inputted to an automatic temperature controller. If the load on the dryer is reduced, the value of the thermometer is lowered than a set value, then an output signal corresponding to the change is supplied from the automatic temperature controller to the heater to forcively apply loads to the dryer. Therefore, defrosting can be conducted completely without operating a refrigerator, and the refrigerator can be maintained under a constant load by applying a dummy load when the load in the dryer is reduced. (I.N.)

  13. Trace emissions from gaseous combustion

    Energy Technology Data Exchange (ETDEWEB)

    Seebold, J.G. [Chevron Research and Technology Co., Richmond, CA (United States)

    2000-07-01

    The U.S. Clean Air Act (CAA) was amended in 1990 to include the development of maximum achievable control technology (MACT) emission standards for hazardous air pollutants (HAPs) for certain stationary sources by November 2000. MACT emissions standards would affect process heaters and industrial boilers since combustion processes are a potential source for many air toxins. The author noted that one of the problems with MACT is the lack of a clear solid scientific footing which is needed to develop environmentally responsible regulations. In order to amend some of these deficiencies, a 4-year, $7 million research project on the origin and fate of trace emissions in the external combustion of gaseous hydrocarbons was undertaken in a collaborative effort between government, universities and industry. This collaborative project entitled the Petroleum Environmental Research Forum (PERF) Project 92-19 produced basic information and phenomenological understanding in two important areas, one basic and one applied. The specific objectives of the project were to measure emissions while operating different full-scale burners under various operating conditions and then to analyze the emission data to identify which operating conditions lead to low air toxic emissions. Another objective was to develop new chemical kinetic mechanisms and predictive models for the formation of air toxic species which would explain the origin and fate of these species in process heaters and industrial boilers. It was determined that a flame is a very effective reactor and that trace emissions from a typical gas-fired industry burner are very small. An unexpected finding was that trace emissions are not affected by hydrocarbon gaseous fuel composition, nor by the use of ultra low nitrous oxide burners. 2 refs., 8 figs.

  14. Gaseous phase heat capacity of benzoic acid

    NARCIS (Netherlands)

    Santos, L.M.N.B.F.; Alves da Rocha, M.A.; Gomes, L.R.; Schröder, B.; Coutinho, J.A.P.

    2010-01-01

    The gaseous phase heat capacity of benzoic acid (BA) was proven using the experimental technique called the "in vacuum sublimation/vaporization Calvet microcalorimetry drop method". To overcome known experimental shortfalls, the gaseous phase heat capacity of BA monomer was estimated by ab initio

  15. Behavioral responses of broilers to different gaseous atmospheres

    NARCIS (Netherlands)

    Gerritzen, M.A.; Lambooij, E.; Hillebrand, S.J.W.; Lankhaar, J.A.C.; Pieterse, C.

    2000-01-01

    This study was conducted to determine the differences in behavioral response of broilers when they come into contact for the first time with gas mixtures that can be used for stunning. The six test groups were divided into four experimental groups that were exposed to gas mixtures used for stunning

  16. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    International Nuclear Information System (INIS)

    Hindin, S. G.; Roberts, G. W.

    1980-01-01

    A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst

  17. Radioactive gaseous waste processing device

    International Nuclear Information System (INIS)

    Murakami, Kazuo.

    1997-01-01

    In a radioactive gaseous waste processing device, a dehumidifier in which a lot of hollow thread membranes are bundled and assembled is disposed instead of a dehumidifying cooling device and a dehumidifying tower. The dehumidifier comprises a main body, a great number of hollow thread membranes incorporated in the main body, a pair of fixing members for bundling and fixing both ends of the hollow thread membranes, a pair of caps for allowing the fixing members to pass through and fixing them on both ends of the main body, an off gas flowing pipe connected to one of the caps, a gas exhaustion pipe connected to the other end of the cap and a moisture removing pipeline connected to the main body. A flowrate control valve is connected to the moisture removing pipeline, and the other end of the moisture removing pipeline is connected between a main condensator and an air extraction device. Then, cooling and freezing devices using freon are no more necessary, and since the device uses the vacuum of the main condensator as a driving source and does not use dynamic equipments, labors for the maintenance is greatly reduced to improve economical property. The facilities are reduced in the size thereby enabling to use space effectively. (N.H.)

  18. Device for filtering gaseous media

    International Nuclear Information System (INIS)

    Benzel, M.

    1978-01-01

    The air filter system for gaseous radioactive substances consists of a vertical chamber with filter material (charcoal, e.g. impregnated). On one side of the chamber there is an inlet compartment and an outlet compartment. On the other side a guiding compartment turns the gas flow coming from the natural-air side through the lower part of filter chamber to the upper part of the filter. The gas flow leaves the upper part through the outlet conpartment as cleaned-air flow. The filter material may be filled into the chamber from above and drawn off below. For better utilization of the filter material the filter chamber is separated by means of a wall between the inlet and outlet compartment. This partition wall consist of two sheets arranged one above the other provided with slots which may be superposed in alignment. In this case filter material is tickling from the upper part of the chamber into the lower part avoiding to form a crater in the filter bed. (DG) [de

  19. Perspective: Spectroscopy and kinetics of small gaseous Criegee intermediates

    International Nuclear Information System (INIS)

    Lee, Yuan-Pern

    2015-01-01

    The Criegee intermediates, carbonyl oxides proposed by Criegee in 1949 as key intermediates in the ozonolysis of alkenes, play important roles in many aspects of atmospheric chemistry. Because direct detection of these gaseous intermediates was unavailable until recently, previous understanding of their reactions, derived from indirect experimental evidence, had great uncertainties. Recent laboratory detection of the simplest Criegee intermediate CH 2 OO and some larger members, produced from ultraviolet irradiation of corresponding diiodoalkanes in O 2 , with various methods such as photoionization, ultraviolet absorption, infrared absorption, and microwave spectroscopy opens a new door to improved understanding of the roles of these Criegee intermediates. Their structures and spectral parameters have been characterized; their significant zwitterionic nature is hence confirmed. CH 2 OO, along with other products, has also been detected directly with microwave spectroscopy in gaseous ozonolysis reactions of ethene. The detailed kinetics of the source reaction, CH 2 I + O 2 , which is critical to laboratory studies of CH 2 OO, are now understood satisfactorily. The kinetic investigations using direct detection identified some important atmospheric reactions, including reactions with NO 2 , SO 2 , water dimer, carboxylic acids, and carbonyl compounds. Efforts toward the characterization of larger Criegee intermediates and the investigation of related reactions are in progress. Some reactions of CH 3 CHOO are found to depend on conformation. This perspective examines progress toward the direct spectral characterization of Criegee intermediates and investigations of the associated reaction kinetics, and indicates some unresolved problems and prospective challenges for this exciting field of research

  20. Sevoflurane improves gaseous exchange and exerts protective ...

    African Journals Online (AJOL)

    Sevoflurane improves gaseous exchange and exerts protective effects in ... Lung water content and cell count were estimated by standard protocols. ... It reversed LPS-induced oxidative stress, as demonstrated by increase in total antioxidant ...

  1. Purifying hydrocarbons in the gaseous stage

    Energy Technology Data Exchange (ETDEWEB)

    1937-02-01

    Gaseous tar oils are subjected, at temperatures of 320 to 380/sup 0/C, to the action of a mixture of activated carbon mixed with powdered metal which removes the sulfur contamination from the substance to be purified.

  2. Automated sampling and control of gaseous simulations

    KAUST Repository

    Huang, Ruoguan; Keyser, John

    2013-01-01

    In this work, we describe a method that automates the sampling and control of gaseous fluid simulations. Several recent approaches have provided techniques for artists to generate high-resolution simulations based on a low-resolution simulation

  3. The conditions of gaseous fuels development

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Face to the actual situation of petrol and gas oil in France, the situation of gaseous fuels appears to be rather modest. However, the aim of gaseous fuels is not to totally supersede the liquid fuels. Such a situation would imply a complete overturn which has not been seriously considered yet. This short paper describes the essential conditions to promote the wider use of gaseous fuels: the intervention of public authorities to adopt a more advantageous tax policy in agreement with the ''Clean Air''law project, a suitable distribution network for gaseous fuels, a choice of vehicles consistent with the urban demand, the development of transformation kits of quality and of dual-fuel vehicles by the car manufacturers. (J.S.)

  4. 7th International Symposium on Gaseous Dielectrics

    CERN Document Server

    James, David

    1994-01-01

    The Seventh International Symposium on Gaseous Dielectrics was held in Knoxville, Tennessee, U. S. A. , on April 24-28, 1994. The symposium continued the interdisciplinary character and comprehensive approach of the preceding six symposia. Gaseous DielecIries VII is a detailed record of the symposium proceedings. It covers recent advances and developments in a wide range of basic, applied and industrial areas of gaseous dielectrics. It is hoped that Gaseous DielecIries VII will aid future research and development in, and encourage wider industrial use of, gaseous dielectrics. The Organizing Committee of the Seventh International Symposium on Gaseous Dielectrics consisted of G. Addis (U. S. A. ), L. G. Christophorou (U. S. A. ), F. Y. Chu (Canada), A. H. Cookson (U. S. A. ), O. Farish (U. K. ), I. Gallimberti (Italy) , A. Garscadden (U. S. A. ), D. R. James (U. S. A. ), E. Marode (France), T. Nitta (Japan), W. Pfeiffer (Germany), Y. Qiu (China), I. Sauers (U. S. A. ), R. J. Van Brunt (U. S. A. ), and W. Zaengl...

  5. Test emission of uranium hexafluoride in atmosphere. Results interpretation

    International Nuclear Information System (INIS)

    Crabol, B.; Deville-Cavelin, G.

    1989-01-01

    To permit the modelization of gaseous uranium hexafluoride behaviour in atmosphere, a validation test has been executed the 10 April 1987. The experimental conditions, the main results and a comparison with a diffusion model are given in this report [fr

  6. Additive Manufacturing Materials Study for Gaseous Radiation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Steer, C.A.; Durose, A.; Boakes, J. [AWE Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom)

    2015-07-01

    Additive manufacturing (AM) techniques may lead to improvements in many areas of radiation detector construction; notably the rapid manufacturing time allows for a reduced time between prototype iterations. The additive nature of the technique results in a granular microstructure which may be permeable to ingress by atmospheric gases and make it unsuitable for gaseous radiation detector development. In this study we consider the application of AM to the construction of enclosures and frames for wire-based gaseous radiation tracking detectors. We have focussed on oxygen impurity ingress as a measure of the permeability of the enclosure, and the gas charging and discharging curves of several simplistic enclosure shapes are reported. A prototype wire-frame is also presented to examine structural strength and positional accuracy of an AM produced frame. We lastly discuss the implications of this study for AM based radiation detection technology as a diagnostic tool for incident response scenarios, such as the interrogation of a suspect radiation-emitting package. (authors)

  7. Additive Manufacturing Materials Study for Gaseous Radiation Detection

    International Nuclear Information System (INIS)

    Steer, C.A.; Durose, A.; Boakes, J.

    2015-01-01

    Additive manufacturing (AM) techniques may lead to improvements in many areas of radiation detector construction; notably the rapid manufacturing time allows for a reduced time between prototype iterations. The additive nature of the technique results in a granular microstructure which may be permeable to ingress by atmospheric gases and make it unsuitable for gaseous radiation detector development. In this study we consider the application of AM to the construction of enclosures and frames for wire-based gaseous radiation tracking detectors. We have focussed on oxygen impurity ingress as a measure of the permeability of the enclosure, and the gas charging and discharging curves of several simplistic enclosure shapes are reported. A prototype wire-frame is also presented to examine structural strength and positional accuracy of an AM produced frame. We lastly discuss the implications of this study for AM based radiation detection technology as a diagnostic tool for incident response scenarios, such as the interrogation of a suspect radiation-emitting package. (authors)

  8. Research on solubility characteristics of gaseous methyl iodide

    International Nuclear Information System (INIS)

    Zhou Yanmin; Sun Zhongning; Gu Haifeng; Wang Junlong

    2014-01-01

    With the deionized water as the absorbent, the solubility characteristics of the gaseous methyl iodide were studied under different temperature and pressure conditions, using a dynamic measuring method. The results show that within the range of experiment parameters, namely temperature is below 80℃ and pressure is lower than 0.3 MPa, the physical dissolution process of gaseous methyl iodide in water obeys Henry's law. The solubility coefficient under different temperature and pressure conditions was calculated based on the measurement results. Further research indicates that at atmospheric pressure, the solubility coefficient of methyl iodide in water decreases exponentially with the increase of temperature. While the pressure changes from 0.1 MPa to 0.3 MPa with equal interval, the solubility coefficient also increases linearly. The variation of the solubility coefficient with temperature under different pressure conditions all decreases exponentially. An equation is given to calculate the solubility coefficient of methyl iodide under different pressure and temperature conditions. (authors)

  9. Gaseous fuel reactors for power systems

    Science.gov (United States)

    Kendall, J. S.; Rodgers, R. J.

    1977-01-01

    Gaseous-fuel nuclear reactors have significant advantages as energy sources for closed-cycle power systems. The advantages arise from the removal of temperature limits associated with conventional reactor fuel elements, the wide variety of methods of extracting energy from fissioning gases, and inherent low fissile and fission product in-core inventory due to continuous fuel reprocessing. Example power cycles and their general performance characteristics are discussed. Efficiencies of gaseous fuel reactor systems are shown to be high with resulting minimal environmental effects. A technical overview of the NASA-funded research program in gaseous fuel reactors is described and results of recent tests of uranium hexafluoride (UF6)-fueled critical assemblies are presented.

  10. Contribution to the study of gaseous molecular iodine washout by natural rains

    International Nuclear Information System (INIS)

    Fournier-Bidoz, V.

    1991-01-01

    This study is part of researches about nuclear accident prediction consequences on the environment. It concerns transfering of molecular gaseous iodine into liquids and especially precipitation scavenging below the cloud (washout). Bibliographic data directly concerned with this study (iodine's aqueous chemistry, aqueous to gaseous phases transfer) and also with its global frame-work (atmospheric release from a nuclear reactor in accidental situation and the behaviour of atmospheric iodine) are presented. Several experimental approaches have been performed in laboratory and on field. An aqueous to gaseous phase transfer simulator allowed us to isolate parameters involved in absorption and desorption of the halogen. Field experiments permit to quantify dry deposition on different solutions and to get a better insight of the phenomenon. Extrapolation of the whole results to precipitation scavenging of gaseous iodine I 2 by natural rains suggests that the process is an irreversible one. Washout rate values acquired during rainy experiments with molecular iodine emission or in a laboratory rainfall simulator agree with literatures data relative to irreversibility. However and even if reversibility was efficient it was not possible to clearly exhibit it according to experimental conditions. Moreover, the analytical iodine method which leads to a good experimental study has been presented

  11. Dynamical instability of a charged gaseous cylinder

    Science.gov (United States)

    Sharif, M.; Mumtaz, Saadia

    2017-10-01

    In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

  12. Entrapment process of radioactive gaseous wastes

    International Nuclear Information System (INIS)

    Gagneraud, Francis; Gagneraud, Michel.

    1981-01-01

    Process for collecting chemically inert gaseous radioactive waste in melted substances, whereby the gaseous waste is injected under pressure in a molten substance to its saturation point followed by fast cooling. This substance is constituted of glass, ceramics, metallurgical drosses and slag masses in fusion. Its cooling is carried out by quenching by means of running water or a gas fluid, or by casting into vessels with great thermal inertia such as cast iron or similar, before recovery and confinement in receptacles for storage [fr

  13. Legal provisions governing gaseous effluents radiological monitoring

    International Nuclear Information System (INIS)

    Winkelmann, I.

    1985-01-01

    This contribution explains the main provisions governing radiological monitoring of gaseous effluents from LWR type nuclear power plants. KTA rule 1503.1 defines the measuring methods and tasks to be fulfilled by reactor operators in order to safeguard due monitoring and accounting of radioactive substances in the plants' gaseous effluents. The routine measurements are checked by a supervisory programme by an independent expert. The routine controls include analysis of filter samples, comparative measurement of radioactive noble gases, interlaboratory comparisons, and comparative evaluation of measured values. (DG) [de

  14. Gaseous Electronics Tables, Atoms, and Molecules

    CERN Document Server

    Raju, Gorur Govinda

    2011-01-01

    With the constant emergence of new research and application possibilities, gaseous electronics is more important than ever in disciplines including engineering (electrical, power, mechanical, electronics, and environmental), physics, and electronics. The first resource of its kind, Gaseous Electronics: Tables, Atoms, and Molecules fulfills the author's vision of a stand-alone reference to condense 100 years of research on electron-neutral collision data into one easily searchable volume. It presents most--if not all--of the properly classified experimental results that scientists, researchers,

  15. Model for absorption and release of gaseous materials by forest canopies

    International Nuclear Information System (INIS)

    Murphy, C.E. Jr.

    1976-01-01

    A model of the physical processes defining the absorption and release of materials by a forest canopy has been developed. The model deals with the turbulent transport of gaseous materials in the surface boundary layer near the canopy, the turbulent transport in the canopy atmosphere, the transport through the boundary layer near the leaf and soil surface, and the solution of the gaseous materials in intracellular fluids and subsequent diffusion into the leaf cells. The model is used to simulate the uptake of molecular tritium by the forest canopy and the subsequent release of tritiated water. Results of dynamic simulations of tritium uptake and release are compared with data collected at the time of a release of molecular tritium to the atmosphere

  16. Dynamic Oxidation of Gaseous Mercury in the Arctic Troposphere at Polar Sunrise

    DEFF Research Database (Denmark)

    Lindberg, S. E.; Brooks, S.; Lin, C.-J.

    2002-01-01

    Gaseous elemental mercury (Hg0) is a globally distributed air toxin with a long atmospheric residence time. Any process that reduces its atmospheric lifetime increases its potential accumulation in the biosphere. Our data from Barrow, AK, at 71 degrees N show that rapid, photochemically driven...... oxidation of boundary-layer Hg0 after polar sunrise, probably by reactive halogens, creates a rapidly depositing species of oxidized gaseous mercury in the remote Arctic troposphere at concentrations in excess of 900 pg m(-3). This mercury accumulates in the snowpack during polar spring at an accelerated...... rate in a form that is bioavailable to bacteria and is released with snowmelt during the summer emergence of the Arctic ecosystem. Evidence suggests that this is a recent phenomenon that may be occurring throughout the earth's polar regions. Udgivelsesdato: 2002-Mar-15...

  17. Portsmouth gaseous diffusion plant environmental monitoring report for calendar year 1975

    International Nuclear Information System (INIS)

    Martin, W.E.; Netzer, W.D.

    1976-01-01

    At the Portsmouth Gaseous Diffusion Plant the ambient atmosphere and all effluent streams are sampled and analyzed regularly for conformance to applicable environmental standards. Although neither the State of Ohio nor the federal government has established standards for fluorides in the ambient atmosphere or in vegetation, these parameters also are monitored because fluoride compounds are used extensively in the gaseous diffusion process. Radioactivity is measured in air, water, food, soil, and sediments; and radiation doses are calculated for the public. All public radiation doses are well within federal standards. Non-radioactive effluent parameters either comply with federal standards, or there are projects planned to allow compliance. A disposal facility to remove chromium from recirculating cooling water blowdown will begin operation in June 1976. Also, pH adjustment facilities for liquid effluents and electrostatic precipitators for a coal-fired steam plant are planned for the near future

  18. Behaviour of radioiodine in gaseous effluents

    International Nuclear Information System (INIS)

    Barry, P.J.

    1968-01-01

    Because of the different chemical forms in which radioiodine occurs in the gaseous state, it is important when designing efficient filters to know the chemical forms which may be present in the effluent gases when various operations are being carried out and to know the effect of different gaseous environments on the filtration efficiency. To obtain this information it is necessary to have available reliable means of characterizing different chemical forms and to sample gaseous effluents when these operations are being carried out. This paper describes the use for identifying molecular iodine of metallic screens in a multi-component sampling pack in different gaseous environments. Using multi-component sampling packs, the fractionation of iodine nuclides between different chemical forms was measured in the effluent gases escaping from an in-pile test loop in which the fuel was deliberately ruptured by restricting the flow of coolant. Sequential samples were taken for six hours after the rupture and it was possible to follow during this period the individual behaviours of 13 '1I, 133 I and 135 I. Simultaneous samples were also obtained of the noble gases in the effluent gas stream and of the iodine nuclides in the loop coolant. Similar experiments have been carried out with a view to characterizing the different chemical behaviour of radioiodine as it is released from a variety of operations in the nuclear industry including the cutting of fuel sections in metallurgical examination caves and an incinerator. (author)

  19. Respiratory system. Part 2: Gaseous exchange.

    Science.gov (United States)

    McLafferty, Ella; Johnstone, Carolyn; Hendry, Charles; Farley, Alistair

    This article, which isthe last in the life sciences series and the second of two articles on the respiratory system, describes gaseous exchange in the lungs, transport of oxygen and carbon dioxide, and internal and external respiration. The article concludes with a brief consideration of two conditions that affect gas exchange and transport: carbon monoxide poisoning and chronic obstructive pulmonary disease.

  20. Technological aspects of gaseous pixel detectors fabrication

    NARCIS (Netherlands)

    Blanco Carballo, V.M.; Salm, Cora; Smits, Sander M.; Schmitz, Jurriaan; Melai, J.; Chefdeville, M.A.; van der Graaf, H.

    2007-01-01

    Integrated gaseous pixel detectors consisting of a metal punctured foil suspended in the order of 50μm over a pixel readout chip by means by SU-8 insulating pillars have been fabricated. SU-8 is used as sacrificial layer but metallization over uncrosslinked SU-8 presents adhesion and stress

  1. Controlled atmosphere for fabrication of cermet electrodes

    Science.gov (United States)

    Ray, Siba P.; Woods, Robert W.

    1998-01-01

    A process for making an inert electrode composite wherein a metal oxide and a metal are reacted in a gaseous atmosphere at an elevated temperature of at least about 750.degree. C. The metal oxide is at least one of the nickel, iron, tin, zinc and zirconium oxides and the metal is copper, silver, a mixture of copper and silver or a copper-silver alloy. The gaseous atmosphere has an oxygen content that is controlled at about 5-3000 ppm in order to obtain a desired composition in the resulting composite.

  2. Uranium enrichment by the gaseous diffusion process

    International Nuclear Information System (INIS)

    Petit, J.F.

    1977-01-01

    After a brief description of the process and technology (principle, stage constitution, cascade constitution, and description of a plant), the author gives the history of gaseous diffusion and describes the existing facilities. Among the different enrichment processes contemplated in the USA during and after the last world war, gaseous diffusion has been the only one to be developed industrially on a wide scale in the USA, then in the UK, in the USSR and in France. The large existing capacities in the USA provided the country with a good starting base for the development of a light-water nuclear power plant programme, the success of which led to a shortfall in production means. France and the USA, possessing the necessary know-how, have been able to undertake the realization of two industrial programmes: the CIP-CUP programme in the USA and the Eurodif project in France. Current plans still call for the construction of several plants by 1990. Can the gaseous diffusion process meet this challenge. Technically, there is no doubt about it. Economically, this process is mainly characterized by large energy consumption and the necessity to build large plants. This leads to a large investment, at least for the first plant. Other processes have been developed with a view to reducing both energy and capital needs. However, in spite of continuous studies and technological progress, no process has yet proved competitive. Large increments in capacities are still expected to come from gaseous diffusion, and several projects taking into account the improvements in flexibility, automatization, reliability and reduced investment, are analysed in the paper. Combining new facilities with existing plants has already proved to be of great interest. This situation explains why gaseous diffusion is being further investigated and new processes are being studied. (author)

  3. Introduction to investigations of the negative corona and EHD flow in gaseous two-phase fluids

    Science.gov (United States)

    Jerzy, MIZERACZYK; Artur, BERENDT

    2018-05-01

    Research interests have recently been directed towards electrical discharges in multi-phase environments. Natural electrical discharges, such as lightning and coronas, occur in the Earth’s atmosphere, which is actually a mixture of gaseous phase (air) and suspended solid and liquid particulate matters (PMs). An example of an anthropogenic gaseous multi-phase environment is the flow of flue gas through electrostatic precipitators (ESPs), which are generally regarded as a mixture of a post-combustion gas with solid PM and microdroplets suspended in it. Electrical discharges in multi-phase environments, the knowledge of which is scarce, are becoming an attractive research subject, offering a wide variety of possible discharges and multi-phase environments to be studied. This paper is an introduction to electrical discharges in multi-phase environments. It is focused on DC negative coronas and accompanying electrohydrodynamic (EHD) flows in a gaseous two-phase fluid formed by air (a gaseous phase) and solid PM (a solid phase), run under laboratory conditions. The introduction is based on a review of the relevant literature. Two cases will be considered: the first case is of a gaseous two-phase fluid, initially motionless in a closed chamber before being subjected to a negative corona (with the needle-to-plate electrode arrangement), which afterwards induces an EHD flow in the chamber, and the second, of a gaseous two-phase fluid flowing transversely with respect to the needle-to-plate electrode axis along a chamber with a corona discharge running between the electrodes. This review-based introductory paper should be of interest to theoretical researchers and modellers in the field of negative corona discharges in single- or two-phase fluids, and for engineers who work on designing EHD devices (such as ESPs, EHD pumps, and smoke detectors).

  4. Photosensitive Gaseous Detectors for Cryogenic Temperature Applications

    CERN Document Server

    Periale, L; Iacobaeus, C; Lund-Jensen, B; Picchi, P; Pietropaolo, F

    2007-01-01

    There are several proposals and projects today for building LXe Time Projection Chambers (TPCs) for dark matter search. An important element of these TPCs are the photomultipliers operating either inside LXe or in vapors above the liquid. We have recently demonstrated that photosensitive gaseous detectors (wire type and hole-type) can operate perfectly well until temperatures of LN2. In this paper results of systematic studies of operation of the photosensitive version of these detectors (combined with reflective or semi-transparent CsI photocathodes) in the temperature interval of 300-150 K are presented. In particular, it was demonstrated that both sealed and flushed by a gas detectors could operate at a quite stable fashion in a year/time scale. Obtained results, in particular the long-term stability of photosensitive gaseous detectors, strongly indicate that they can be cheap and simple alternatives to photomultipliers or avalanche solid-state detectors in LXe TPC applications.

  5. Basic processes and trends in gaseous detectors

    CERN Multimedia

    1999-01-01

    Almost a century after the invention of the proportional counter, a large research effort is still devoted to better understand the basic properties of gaseous detectors, and to improve their performances and reliability, particularly in view of use at the high radiation levels expected at LHC. In the first part of the lectures, after a brief introduction on underlying physical phenomena, I will review modern sophisticated computational tools, as well as some classic "back of the envelope" analytical methods, available today for estimating the general performances of gaseous detectors. In the second part, I will analyze in more detail problems specific to the use of detectors at high rates (space charge, discharges, aging), and describe the recent development of powerful and perhaps more reliable devices, particularly in the field of position-sensitive micro-pattern detectors.

  6. Secondary incinerator for radioactive gaseous waste

    International Nuclear Information System (INIS)

    Takeda, Tadashi; Masuda, Takashi.

    1997-01-01

    A vessel incorporated with packings, in which at least either of the packings and the vessel is put to induction-heating by high frequency induction coils, is disposed in a flow channel of radioactive gaseous wastes exhausted from a radioactive waste incinerator. The packings include metals such as stainless pipes and electroconductive ceramics such as C-SiC ceramics. Since only electricity is used as an energy source, in the secondary incinerator for the radioactive gaseous wastes, it can be installed in a cell safely. In addition, if ceramics are used, there is no worry of deterioration of the incinerator due to organic materials, and essential functions are not lowered. (T.M.)

  7. Trends and new developments in gaseous detectors

    CERN Document Server

    AUTHOR|(CDS)2069485

    2004-01-01

    Almost one century ago the method of particle detection with gaseous detectors was invented. Since then they have been exploited successfully in many experiments using a wide variety of different applications. The development is still going on today. The underlying working principles are today well understood and with the help of modern simulation techniques, new configurations can be easily examined and optimized before a first experimental test. Traditional wire chamber ensembles demonstrate that they are still up to date and are well prepared to meet also the challenges of LHC. Applications will be discussed using TPCs in high multiplicity environments with standard Multi-Wire Proportional Chamber (MWPC) as readout as well as drift tubes in a muon spectrometer for a Large Hadron Collider (LHC) experiment. Triggered by the evolving printed circuit technology, a new generation of gaseous detectors with very high position resolution and rate capability has emerged. Two representatives (MICROMEGAS, GEM) have p...

  8. National Gas Survey. Synthesized gaseous hydrocarbon fuels

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-06-01

    The supply-Technical Advisory Task Force-Synthesized Gaseous Hydrocarbon Fuels considered coal, hydrocarbon liquids, oil shales, tar sands, and bioconvertible materials as potential feedstocks for gaseous fuels. Current status of process technology for each feedstock was reviewed, economic evaluations including sensitivity analysis were made, and constraints for establishment of a synthesized gaseous hydrocarbon fuels industry considered. Process technology is presently available to manufacture gaseous hydrocarbon fuels from each of the feedstocks. In 1975 there were eleven liquid feedstock SNG plants in the United States having a capacity of 1.1 billion SCFD. There can be no contribution of SNG before 1982 from plants using feedstocks other than liquids because there are no plants in operation or under construction as of 1977. Costs for SNG are higher than current regulated prices for U.S. natural gas. Because of large reserves, coal is a prime feedstock candidate although there are major constraints in the area of coal leases, mining and water permits, and others. Commercial technology is available and several new gasification processes are under development. Oil shale is also a feedstock in large supply and commercial process technology is available. There are siting and permit constraints, and water availability may limit the ultimate size of an oil shale processing industry. Under projected conditions, bioconvertible materials are not expected to support the production of large quantities of pipeline quality gas during the next decade. Production of low or medium Btu gas from municipal solid wastes can be expected to be developed in urban areas in conjunction with savings in disposal costs. In the economic evaluations presented, the most significant factor for liquid feedstock plants is the anticipated cost of feedstock and fuel. The economic viability of plants using other feedstocks is primarily dependent upon capital requirements.

  9. Polarization measurement for internal polarized gaseous targets

    International Nuclear Information System (INIS)

    Ye Zhenyu; Ye Yunxiu; Lv Haijiang; Mao Yajun

    2004-01-01

    The authors present an introduction to internal polarized gaseous targets, polarization method, polarization measurement method and procedure. To get the total nuclear polarization of hydrogen atoms (including the polarization of the recombined hydrogen molecules) in the target cell, authors have measured the parameters relating to atomic polarization and polarized hydrogen atoms and molecules. The total polarization of the target during our measurement is P T =0.853 ± 0.036. (authors)

  10. Uranium enrichment export control guide: Gaseous diffusion

    Energy Technology Data Exchange (ETDEWEB)

    1989-09-01

    This document was prepared to serve as a guide for export control officials in their interpretation, understanding, and implementation of export laws that relate to the Zangger International Trigger List for gaseous diffusion uranium enrichment process components, equipment, and materials. Particular emphasis is focused on items that are especially designed or prepared since export controls are required for these by States that are party to the International Nuclear Nonproliferation Treaty.

  11. A new gaseous gap conductance relationship

    International Nuclear Information System (INIS)

    Wesley, D.A.; Yovanovich, M.M.

    1986-01-01

    A new relationship for predicting the gaseous gap conductance between the fuel and clad of a nuclear fuel rod is derived. This relationship is derived from purely analytical considerations and represents a departure from approaches taken in the past. A comparison between the predictions from this new relationship and experimental measurements is presented and the agreement is very good. Predictions can be generated relatively quickly with this relationship making it attractive for fuel pin analysis codes

  12. Growth of planetisimals in a gaseous ring

    International Nuclear Information System (INIS)

    Hourigan, K.

    1981-01-01

    The aggregation of planetesimals in a gaseous ring leads to the development of a dominant body amongst the planetesimal population. The presence of the gas in the form of a differentially rotating ring serves to constrain the orbits of the planetesimals and grains to within a thin toroidal region through the action of gas drag. This situation allows for the efficient aggregation of bodies and, as a result of the low resultant relative velocites, the minimization of collisional fragmentation effects

  13. 2 π gaseous flux proportional detector

    International Nuclear Information System (INIS)

    Guevara, E.A.; Costello, E.D.; Di Carlo, R.O.

    1986-01-01

    A counting system has been developed in order to measure carbon-14 samples obtained in the course of a study of a plasmapheresis treatment for diabetic children. The system is based on the use of a 2π gaseous flux proportional detector especially designed for the stated purpose. The detector is described and experiment results are given, determining the characteristic parameters which set up the working conditions. (Author) [es

  14. EURODIF: the uranium enrichment by gaseous diffusion

    International Nuclear Information System (INIS)

    Rougeau, J.P.

    1981-01-01

    During the seventies the nuclear power programme had an extremely rapid growth rate which entailed to increase the world uranium enrichment capacity. EURODIF is the largest undertaking in this field. This multinational joint venture built and now operates and enrichment plant using the gaseous diffusion process at Tricastin (France). This plant is delivering low enriched uranium since two years and has contracted about 110 million SWU's till 1990. Description, current activity and prospects are given in the paper. (Author) [pt

  15. Correlation and prediction of gaseous diffusion coefficients.

    Science.gov (United States)

    Marrero, T. R.; Mason, E. A.

    1973-01-01

    A new correlation method for binary gaseous diffusion coefficients from very low temperatures to 10,000 K is proposed based on an extended principle of corresponding states, and having greater range and accuracy than previous correlations. There are two correlation parameters that are related to other physical quantities and that are predictable in the absence of diffusion measurements. Quantum effects and composition dependence are included, but high-pressure effects are not. The results are directly applicable to multicomponent mixtures.

  16. Lichens and atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, J H

    1964-09-01

    The extreme sensitivity of lichens, particularly the larger ones, to industrialization has been recognized for many years. Most people attribute the absence of lichens from urban areas to the atmospheric pollution prevailing, and a few attribute it to climatic dryness, resulting from efficient drainage systems in towns. The two main components of air pollution are solid matter, or soot, and gaseous sulfur dioxide. The main effects of pollution appear to be: a direct reduction of light intensity by smoke haze, a deposit of soot on the plant surface, an acidification of the soil, and direct damage to plants. A body of evidence indicates that SO/sub 2/ may be the main harmful component for lichens. The distribution of lichens thus might be used to determine the limits within which atmospheric pollution is operating. 5 references.

  17. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  18. Bench-scale and full-scale studies of nitric oxides reduction by gaseous fuel reburning

    International Nuclear Information System (INIS)

    Su, S.; Xiang, J.; Sun, L.S.; Hu, S.; Zhu, J.M.

    2008-01-01

    Nitrogen oxides (NOx) emissions from coal-fired boilers are significant contributors to atmospheric pollution. China has specified more rigorous legal limits for NOx emissions from power plants. As a result of the need to reduce NOx emissions, cost-effective NOx reduction strategies must be explored. This paper presented detailed experimental studies on a gaseous fuel reburning process that was performed in a 36 kilowatt bench-scale down-fired furnace to define the optimal reburning operating conditions when different Chinese coals were fired in the furnace. In addition, the combustion system of a 350 megawatt full-scale boiler was retrofitted according to the experimental results. Finally, the gaseous fuel reburning was applied to the retrofitted full-scale boiler. The purpose of the study was to obtain a better understanding of the influence of the key parameters on nitric oxide (NO) reduction efficiency of the reburning process and demonstrate the gaseous fuel reburning on a 350 MWe coal-fired boiler in China. The paper described the experimental procedure with particular reference to the experimental facility and measurement; a schematic diagram of the experimental system; experimental fuels; and characteristics of coals for the reburning experiments. Results that were presented included influence of reburn zone residence time; influence of gaseous reburn fuel per cent; influence of excess air coefficient; and unburned carbon in fly ash. It was concluded that both an above 50 per cent NO reduction efficiency and low carbon loss can be obtained by the gaseous fuel reburning process under the optimal operating conditions. 20 refs., 5 tabs., 10 figs

  19. Hazardous gas treatment by atmospheric discharges

    International Nuclear Information System (INIS)

    Mizeraczyk, J.

    2005-01-01

    The emissions of NO x ; SO x , CO 2 and volatile organic compounds (VOCs) including fluorocarbons to the atmosphere influence heavily our environment, NO x and SO x emitted to the atmosphere are the major cause of acid rains, while CO 2 and VOCs emissions cause the greenhouse effect which leads to abnormal global heating of the atmosphere and creating in a temperature inversion layer that traps gaseous pollutants. Therefore, there is an increasing interest in controlling these emissions. A new technique, which uses the plasma processes induced by energetic electrons, emerges as one of the most effective methods of reducing concentrations of the emitted gaseous pollutants. Various plasma techniques have been tested for gaseous pollution control. The electron bean irradiation was found to be physically and economically efficient for NO x and SO x reduction in the exhaust gases from electrical and heat power plants. The capability of the non-thermal plasmas, produced in atmospheric pressure electrical discharges, for decomposition of the gaseous pollutants has been widely tested. These atmospheric pressure electrical discharges are dielectric barrier discharges, pulsed and de corona discharges (in the reactors with the point-to-plate, wire-cylinder and wire-plate geometries, in the reactors with flow stabilized corona torch and corona radical shower), gliding discharges, inductively coupled high-frequency discharges, ac surface discharges, ac discharges in the packed bed reactors, and microwave torch discharges. In this paper, after reviewing the methods and devices used for producing the non-thermal plasmas for gaseous pollutant control, some results of the laboratory experiments on the plasmas abatement of NO x ; SO x and various VOCs will be presented, followed by a discussion on the energy efficiency and by-products. Also some results obtained in the pilot-plants will be given. finally other possible applications of the presented plasma devices for controlling

  20. Method for separating gaseous mixtures of isotopes

    International Nuclear Information System (INIS)

    Neimann, H.J.; Schuster, E.; Kersting, A.

    1976-01-01

    A gaseous mixture of isotopes is separated by laser excitation of the isotope mixture with a narrow band of wavelengths, molecularly exciting mainly the isotope to be separated and thereby promoting its reaction with its chemical partner which is excited in a separate chamber. The excited isotopes and the chemical partner are mixed, perhaps in a reaction chamber to which the two excited components are conducted by very short conduits. The improvement of this method is the physical separation of the isotope mixture and its partner during excitation. The reaction between HCl and the mixture of 238 UF 6 and 235 UF 6 is discussed

  1. Treatment of gaseous and airborne radioactive waste

    International Nuclear Information System (INIS)

    Leichsenring, C.H.

    1982-01-01

    Gaseous and airborne radionuclides in the fuel cycle are retained in vessel off-gas filter systems and in the dissolver off-gas cleaning system. Those systems have to meet the regulatory requirements for both normal and accident conditions. From the solutions liquid aerosols are formed during liquid transfer (air lifts, steam jets) or by air sparging or by evaporation processes. During dissolution the volatile radionuclides i.e. 85 Kr, 129 I and 14 C are liberated and enter into the dissolver off-gas cleaning system. Flow sheets of different cleaning systems and their stage of development are described. (orig./RW)

  2. Progress in GEM-based gaseous photomultipliers

    CERN Document Server

    Chechik, R; Breskin, Amos; Buzulutskov, A F; Guedes, G P; Mörmann, D; Singh, B K

    2003-01-01

    We discuss recent progress in gaseous photomultipliers (GPMTs) comprising UV-to-visible spectral range photocathodes (PCs) coupled to multiple Gas Electron Multipliers (GEM). The PCs may be either semitransparent or reflective ones directly deposited on the first-GEM surface. These detectors provide high gain, even in noble gases, are sensitive to single photons, have nanosecond time resolution, and offer good localization. The operation of CsI-based GPMTs in CF sub 4 opens new applications in Cherenkov detectors, where both the radiator and the photosensor operate in the same gas. The latest results on sealed visible-light detectors, combining bialkali PCs and Kapton-made GEMs are presented.

  3. Developments in gaseous core reactor technology

    International Nuclear Information System (INIS)

    Diaz, N.J.; Dugan, E.T.

    1979-01-01

    An effort to characterize the most promising concepts for large, central-station electrical generation was done under the auspices of the Nonproliferation Alternative Systems Assessment Program (NASAP). The two leading candidates were identified from this effort: The Mixed-Flow Gaseous Core Reactor (MFGCR) and the Heterogeneous Gas Core Reactor (HGCR). Key advantages over other nuclear concepts are weighed against the disadvantages of an unproven technology and the cost-time for deployment to make a sound decision on RandD support for these promising reactor alternatives. 38 refs

  4. Novel gaseous detectors for medical imaging

    International Nuclear Information System (INIS)

    Danielsson, M.; Fonte, P.; Francke, T.; Iacobaeus, C.; Ostling, J.; Peskov, V.

    2004-01-01

    We have developed and successfully tested prototypes of two new types of gaseous detectors for medical imaging purposes. The first one is called the Electronic Portal Imaging Device (EPID). It is oriented on monitoring and the precise alignment of the therapeutic cancer treatment beam (pulsed gamma radiation) with respect to the patient's tumor position. The latest will be determined from an X-ray image of the patient obtained in the time intervals between the gamma pulses. The detector is based on a 'sandwich' of hole-type gaseous detectors (GEM and glass microcapillary plates) with metallic gamma and X-ray converters coated with CsI layers. The second detector is an X-ray image scanner oriented on mammography and other radiographic applications. It is based on specially developed by us high rate RPCs that are able to operate at rates of 10 5 Hz/mm 2 with a position resolution better than 50 μm at 1 atm. The quality of the images obtained with the latest version of this device were in most cases more superior than those obtained from commercially available detectors

  5. Gaseous radiocarbon measurements of small samples

    International Nuclear Information System (INIS)

    Ruff, M.; Szidat, S.; Gaeggeler, H.W.; Suter, M.; Synal, H.-A.; Wacker, L.

    2010-01-01

    Radiocarbon dating by means of accelerator mass spectrometry (AMS) is a well-established method for samples containing carbon in the milligram range. However, the measurement of small samples containing less than 50 μg carbon often fails. It is difficult to graphitise these samples and the preparation is prone to contamination. To avoid graphitisation, a solution can be the direct measurement of carbon dioxide. The MICADAS, the smallest accelerator for radiocarbon dating in Zurich, is equipped with a hybrid Cs sputter ion source. It allows the measurement of both, graphite targets and gaseous CO 2 samples, without any rebuilding. This work presents experiences dealing with small samples containing 1-40 μg carbon. 500 unknown samples of different environmental research fields have been measured yet. Most of the samples were measured with the gas ion source. These data are compared with earlier measurements of small graphite samples. The performance of the two different techniques is discussed and main contributions to the blank determined. An analysis of blank and standard data measured within years allowed a quantification of the contamination, which was found to be of the order of 55 ng and 750 ng carbon (50 pMC) for the gaseous and the graphite samples, respectively. For quality control, a number of certified standards were measured using the gas ion source to demonstrate reliability of the data.

  6. Detector for gaseous nuclear fission products

    International Nuclear Information System (INIS)

    Kobayashi, Yoshihiro; Kubo, Katsumi.

    1979-01-01

    Purpose: To facilitate the fabrication of a precipitator type detector, as well as improve the reliability. Constitution: Gas to be measured flown in an anode is stored in a gas processing system. By applying a voltage between the anode and the cathode, if positively charged Rb or Cs which is the daughter products of gaseous fission products are present in the gas to be measured, the daughter products are successively deposited electrostatically to the cathode. The daughter products issue beta-rays and gamma-rays to ionize the argon gas at the anode, whereby ionizing current flows between both of the electrodes. Pulses are generated from the ionizing current, and presence or absence, as well as the amount of the gaseous fission products are determined by the value recorded for the number of the pulses to thereby detect failures in the nuclear fuel elements. After the completion of the detection, the inside of the anode is evacuated and the cathode is heated to evaporate and discharge the daughter products externally. This eliminates the effects of the former detection to the succeeding detection. (Moriyama, K.)

  7. Trends and new developments in gaseous detectors

    International Nuclear Information System (INIS)

    Hoch, M.

    2004-01-01

    Almost one century ago the method of particle detection with gaseous detectors was invented. Since then they have been exploited successfully in many experiments using a wide variety of different applications. The development is still going on today. The underlying working principles are today well understood and with the help of modern simulation techniques, new configurations can be easily examined and optimized before a first experimental test. Traditional wire chamber ensembles demonstrate that they are still up to date and are well prepared to meet also the challenges of LHC. Applications will be discussed using TPCs in high multiplicity environments with standard Multi-Wire Proportional Chamber (MWPC) as readout as well as drift tubes in a muon spectrometer for a Large Hardron Collider (LHC) experiment. Triggered by the evolving printed circuit technology, a new generation of gaseous detectors with very high position resolution and rate capability has emerged. Two representatives (MICROMEGAS, GEM) have proved their reliability in various experiments and are promising candidates for future projects. Performance and results will be discussed for these detectors. Furthermore, achievements in RPC-based detectors will be discussed. The standard Trigger RPC is a reliable low-cost semi-industrial manufactured device with good time resolution. Thin gap RPCs (Multigap-, and High Rate Timing RPC) show very fast signal response at high efficiency and significantly increased rate capability and will be applied in TOF detectors

  8. Trends and new developments in gaseous detectors

    Science.gov (United States)

    Hoch, M.

    Almost one century ago the method of particle detection with gaseous detectors was invented. Since then they have been exploited successfully in many experiments using a wide variety of different applications. The development is still going on today. The underlying working principles are today well understood and with the help of modern simulation techniques, new configurations can be easily examined and optimized before a first experimental test. Traditional wire chamber ensembles demonstrate that they are still up to date and are well prepared to meet also the challenges of LHC. Applications will be discussed using TPCs in high multiplicity environments with standard Multi-Wire Proportional Chamber (MWPC) as readout as well as drift tubes in a muon spectrometer for a Large Hardron Collider (LHC) experiment. Triggered by the evolving printed circuit technology, a new generation of gaseous detectors with very high position resolution and rate capability has emerged. Two representatives (MICROMEGAS, GEM) have proved their reliability in various experiments and are promising candidates for future projects. Performance and results will be discussed for these detectors. Furthermore, achievements in RPC-based detectors will be discussed. The standard Trigger RPC is a reliable low-cost semi-industrial manufactured device with good time resolution. Thin gap RPCs (Multigap-, and High Rate Timing RPC) show very fast signal response at high efficiency and significantly increased rate capability and will be applied in TOF detectors.

  9. Trends and new developments in gaseous detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hoch, M. [CERN, Geneva 23 (Switzerland)]. E-mail: michael.hoch@cern.ch

    2004-12-11

    Almost one century ago the method of particle detection with gaseous detectors was invented. Since then they have been exploited successfully in many experiments using a wide variety of different applications. The development is still going on today. The underlying working principles are today well understood and with the help of modern simulation techniques, new configurations can be easily examined and optimized before a first experimental test. Traditional wire chamber ensembles demonstrate that they are still up to date and are well prepared to meet also the challenges of LHC. Applications will be discussed using TPCs in high multiplicity environments with standard Multi-Wire Proportional Chamber (MWPC) as readout as well as drift tubes in a muon spectrometer for a Large Hardron Collider (LHC) experiment. Triggered by the evolving printed circuit technology, a new generation of gaseous detectors with very high position resolution and rate capability has emerged. Two representatives (MICROMEGAS, GEM) have proved their reliability in various experiments and are promising candidates for future projects. Performance and results will be discussed for these detectors. Furthermore, achievements in RPC-based detectors will be discussed. The standard Trigger RPC is a reliable low-cost semi-industrial manufactured device with good time resolution. Thin gap RPCs (Multigap-, and High Rate Timing RPC) show very fast signal response at high efficiency and significantly increased rate capability and will be applied in TOF detectors.

  10. Position-sensitive gaseous photomultipliers research and applications

    CERN Document Server

    Francke, Tom; Peskov, Vladimir

    2016-01-01

    Gaseous photomultipliers are defined as gas-filled devices capable of recording single ultraviolet (UV) and visible photons with high position resolution. Used in a variety of research areas, these detectors can be paired with computers to treat and store imaging information of UV-light. Position-Sensitive Gaseous Photomultipliers: Research and Applications explores the advancement of gaseous detectors as applied for single photon detection. Emphasizing emerging perspectives and new ways to apply gaseous detectors across research fields, this research-based publication is an essential reference source for engineers, physicists, graduate-level students, and researchers.

  11. Process for exchanging hydrogen isotopes between gaseous hydrogen and water

    International Nuclear Information System (INIS)

    Hindin, S.G.; Roberts, G.W.

    1977-01-01

    A process is described for exchanging isotopes (particularly tritium) between water and gaseous hydrogen. Isotope depleted gaseous hydrogen and water containing a hydrogen isotope are introduced into the vapour phase in a first reaction area. The steam and gaseous hydrogen are brought into contact with a supported metal catalyst in this area in a parallel flow at a temperature range of around 225 and 300 0 C. An effluent flow comprising a mixture of isotope enriched gaseous hydrogen and depleted steam is evacuated from this area and the steam condensed into liquid water [fr

  12. Jovian atmospheres

    International Nuclear Information System (INIS)

    Allison, M.; Travis, L.D.

    1986-10-01

    A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers

  13. Air sampling program at the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Hulett, S.H.

    1975-01-01

    An extensive air sampling program has been developed at the Portsmouth Gaseous Diffusion Plant for monitoring the concentrations of radioactive aerosols present in the atmosphere on plantsite as well as in the environs. The program is designed to minimize exposures of employees and the environment to airborne radioactive particulates. Five different air sampling systems, utilizing either filtration or impaction, are employed for measuring airborne alpha and beta-gamma activity produced from 235 U and 234 Th, respectively. Two of the systems have particle selection capabilities: a personal sampler with a 10-mm nylon cyclone eliminates most particles larger than about 10 microns in diameter; and an Annular Kinetic Impactor collects particulates greater than 0.4 microns in diameter which have a density greater than 12-15 gm/cm 3 . A Hi-Volume Air Sampler and an Eberline Model AIM-3 Scintillation Air Monitor are used in collecting short-term samples for assessing compliance with ''ceiling'' standards or peak concentration limits. A film-sort aperture IBM card system is utilized for continuous 8-hour samples. This sampling program has proven to be both practical and effective for assuring accurate monitoring of the airborne activity associated with plant operations

  14. Development of a passive sampler for gaseous mercury

    Science.gov (United States)

    Gustin, M. S.; Lyman, S. N.; Kilner, P.; Prestbo, E.

    2011-10-01

    Here we describe work toward development of the components of a cost effective passive sampling system for gaseous Hg that could be broadly deployed by nontechnical staff. The passive sampling system included an external shield to reduce turbulence and exposure to precipitation and dust, a diffusive housing that directly protects the collection surface during deployment and handling, and a collection surface. A protocol for cleaning and deploying the sampler and an analytical method were developed. Our final design consisted of a polycarbonate external shield enclosing a custom diffusive housing made from expanded PTFE tubing. Two collection surfaces were investigated, gold sputter-coated quartz plates and silver wires. Research showed the former would require extensive quality control for use, while the latter had interferences with other atmosphere constituents. Although the gold surface exhibited the best performance over space and time, gradual passivation would limit reuse. For both surfaces lack of contamination during shipping, deployment and storage indicated that the handling protocols developed worked well with nontechnical staff. We suggest that the basis for this passive sampling system is sound, but further exploration and development of a reliable collection surface is needed.

  15. Gaseous elemental mercury depletion events observed at Cape Point during 2007–2008

    Directory of Open Access Journals (Sweden)

    E.-G. Brunke

    2010-02-01

    Full Text Available Gaseous mercury in the marine boundary layer has been measured with a 15 min temporal resolution at the Global Atmosphere Watch station Cape Point since March 2007. The most prominent features of the data until July 2008 are the frequent occurrences of pollution (PEs and depletion events (DEs. Both types of events originate mostly within a short transport distance (up to about 100 km, which are embedded in air masses ranging from marine background to continental. The Hg/CO emission ratios observed during the PEs are within the range reported for biomass burning and industrial/urban emissions. The depletion of gaseous mercury during the DEs is in many cases almost complete and suggests an atmospheric residence time of elemental mercury as short as a few dozens of hours, which is in contrast to the commonly used estimate of approximately 1 year. The DEs observed at Cape Point are not accompanied by simultaneous depletion of ozone which distinguishes them from the halogen driven atmospheric mercury depletion events (AMDEs observed in Polar Regions. Nonetheless, DEs similar to those observed at Cape Point have also been observed at other places in the marine boundary layer. Additional measurements of mercury speciation and of possible mercury oxidants are hence called for to reveal the chemical mechanism of the newly observed DEs and to assess its importance on larger scales.

  16. Simulating Isotope Enrichment by Gaseous Diffusion

    Science.gov (United States)

    Reed, Cameron

    2015-04-01

    A desktop-computer simulation of isotope enrichment by gaseous diffusion has been developed. The simulation incorporates two non-interacting point-mass species whose members pass through a cascade of cells containing porous membranes and retain constant speeds as they reflect off the walls of the cells and the spaces between holes in the membranes. A particular feature is periodic forward recycling of enriched material to cells further along the cascade along with simultaneous return of depleted material to preceding cells. The number of particles, the mass ratio, the initial fractional abundance of the lighter species, and the time between recycling operations can be chosen by the user. The simulation is simple enough to be understood on the basis of two-dimensional kinematics, and demonstrates that the fractional abundance of the lighter-isotope species increases along the cascade. The logic of the simulation will be described and results of some typical runs will be presented and discussed.

  17. Gaseous fuel reactors for power systems

    International Nuclear Information System (INIS)

    Helmick, H.H.; Schwenk, F.C.

    1978-01-01

    The Los Alamos Scientific Laboratory is participating in a NASA-sponsored program to demonstrate the feasibility of a gaseous uranium fueled reactor. The work is aimed at acquiring experimental and theoretical information for the design of a prototype plasma core reactor which will test heat removal by optical radiation. The basic goal of this work is for space applications, however, other NASA-sponsored work suggests several attractive applications to help meet earth-bound energy needs. Such potential benefits are small critical mass, on-site fuel processing, high fuel burnup, low fission fragment inventory in reactor core, high temperature for process heat, optical radiation for photochemistry and space power transmission, and high temperature for advanced propulsion systems. Low power reactor experiments using uranium hexafluoride gas as fuel demonstrated performance in accordance with reactor physics predictions. The final phase of experimental activity now in progress is the fabrication and testing of a buffer gas vortex confinement system

  18. Method of eliminating gaseous hydrogen isotopes

    International Nuclear Information System (INIS)

    Nagakura, Masaaki; Imaizumi, Hideki; Suemori, Nobuo; Aizawa, Takashi; Naito, Taisei.

    1983-01-01

    Purpose: To prevent external diffusion of gaseous hydrogen isotopes such as tritium or the like upon occurrence of tritium leakage accident in a thermonuclear reactor by recovering to eliminate the isotopes rapidly and with safety. Method: Gases at the region of a reactor container where hydrogen isotopes might leak are sucked by a recycing pump, dehumidified in a dehumidifier and then recycled from a preheater through a catalytic oxidation reactor to a water absorption tower. In this structure, the dehumidifier is disposed at the upstream of the catalytic oxidation reactor to reduce the water content of the gases to be processed, whereby the eliminating efficiency for the gases to be processed can be maintained well even when the oxidation reactor is operated at a low temperature condition near the ambient temperature. This method is based on the fact that the oxidating reactivity of the catalyst can be improved significantly by eliminating the water content in the gases to be processed. (Yoshino, Y.)

  19. The thermodynamic functions of gaseous actinide elements

    International Nuclear Information System (INIS)

    Rand, M.H.

    1979-01-01

    The actinide gases have large number of unobserved energy states - up to 3 x 10 6 for Pu(g) - which could contribute to the partition function and its derivatives, from which the thermal functions of these gases are calculated. Existing compilations have simply ignored these levels. By making reasonable assumptions as to the distribution of these energy states, their effect on the functions can be calculated. It is concluded that the existing compilations will be inadequate above approximately 2000K. The effect is particularly marked on the heat capacity. For example, when unobserved levels for Pu(g) are included, the heat capacity of Pu(g) reaches a maximum value of more than 12R at 3200K. Similar considerations will apply to the gaseous actinide ions. (orig.) [de

  20. Device for solidification of gaseous wastes

    International Nuclear Information System (INIS)

    Shimada, Masayuki; Kamei, Hisashi.

    1979-01-01

    Purpose: To provide the subject device wherein gaseous wastes such as krypton 85 and the like are ionized and accelerated to be injected into solid targets and stored therein, thereby removing the redischarge of gas and making it possible to treat a large quantity of said gas. Constitution: Krypton gas is ionized and accelerated to high energy by an accelerator, and then introduced into an ion injection chamber. In the ion injection chamber a band-shaped target is delivered from a first take-up roll, and krypton ions are injected to said target. Thereafter, other band-shaped target delivered from a second take-up roll is brought into contact with the target in which krypton ions have been injected, and both targets are taken up together while compressing these targets. In this way, even when injected energy is small, the injected gas is not redischarged and can be continuously treated. (Kamimura, M.)

  1. 2011 GASEOUS IONS GORDON RESEARCH CONFERENCE

    Energy Technology Data Exchange (ETDEWEB)

    Scott Anderson

    2011-03-04

    The Gaseous Ions: Structures, Energetics and Reactions Gordon Research Conference will focus on ions and their interactions with molecules, surfaces, electrons, and light. The conference will cover theory and experiments, and systems ranging from molecular to biological to clusters to materials. The meeting goal continues to be bringing together scientists interested in fundamentals, with those applying fundamental phenomena to a wide range of practical problems. Each of the ten conference sessions will focus on a topic within this spectrum, and there will also be poster sessions for contributed papers, with sufficient space and time to allow all participants to present their latest results. To encourage active participation by young investigators, about ten of the poster abstracts will be selected for 15 minute 'hot topic' talks during the conference sessions. Hot topic selection will be done about a month before the meeting. Funds should be available to offset the participation cost for young investigators.

  2. A new gaseous and combustible form of water

    Energy Technology Data Exchange (ETDEWEB)

    Santilli, Ruggero Maria [Institute for Basic Research, P.O. Box 1577, Palm Harbor, FL 34682 (United States)

    2006-08-15

    In this paper we present, apparently for the first time, various measurements on a mixture of hydrogen and oxygen called HHO gas produced via a new electrolyzer (international patents pending by Hydrogen Technologies Applications, Inc. of Clearwater, Florida), which mixture is distinctly different than the Brown and other known gases. The measurements herein reported suggest the existence in the HHO gas of stable clusters composed of H and O atoms, their dimers H-O, and their molecules H{sub 2}, O{sub 2} and H{sub 2}O whose bond cannot entirely be of valence type. Numerous anomalous experimental measurements on the HHO gas are reported in this paper for the first time. To reach their preliminary, yet plausible interpretation, we introduce the working hypothesis that the clusters constituting the HHO gas constitute another realization of a recently discovered new chemical species called for certain technical reasons magnecules as well as to distinguish them from the conventional 'molecules' [Santilli RM. Foundations of hadronic chemistry with applications to new clean energies and fuels. Boston, Dordrecht, London: Kluwer Academic Publisher; 2001]. It is indicated that the creation of the gaseous and combustible HHO from distilled water at atmospheric temperature and pressure occurs via a process structurally different than evaporation or separation, thus suggesting the existence of a new form of water, apparently introduced in this paper for the first time, with the structure (HxH)-O where 'x' represents the new magnecular bond and '-' the conventional molecular bond. The transition from the conventional H-O-H species to the new (HxH)-O species is predicted by a change of the electric polarization of water caused by the electrolyzer. When H-O-H is liquid, the new species (HxH)-O can only be gaseous, thus explaining the transition of state without evaporation or separation energy. Finally, the new species (HxH)-O is predicted to be

  3. Dry deposition of gaseous oxidized mercury in Western Maryland.

    Science.gov (United States)

    Castro, Mark S; Moore, Chris; Sherwell, John; Brooks, Steve B

    2012-02-15

    The purpose of this study was to directly measure the dry deposition of gaseous oxidized mercury (GOM) in western Maryland. Annual estimates were made using passive ion-exchange surrogate surfaces and a resistance model. Surrogate surfaces were deployed for seventeen weekly sampling periods between September 2009 and October 2010. Dry deposition rates from surrogate surfaces ranged from 80 to 1512 pgm(-2)h(-1). GOM dry deposition rates were strongly correlated (r(2)=0.75) with the weekly average atmospheric GOM concentrations, which ranged from 2.3 to 34.1 pgm(-3). Dry deposition of GOM could be predicted from the ambient air concentrations of GOM using this equation: GOM dry deposition (pgm(-2)h(-1))=43.2 × GOM concentration-80.3. Dry deposition velocities computed using GOM concentrations and surrogate surface GOM dry deposition rates, ranged from 0.2 to 1.7 cms(-1). Modeled dry deposition rates were highly correlated (r(2)=0.80) with surrogate surface dry deposition rates. Using the overall weekly average surrogate surface dry deposition rate (369 ± 340 pg m(-2)h(-1)), we estimated an annual GOM dry deposition rate of 3.2 μg m(-2)year(-1). Using the resistance model, we estimated an annual GOM dry deposition rate of 3.5 μg m(-2)year(-1). Our annual GOM dry deposition rates were similar to the dry deposition (3.3 μg m(-2)h(-1)) of gaseous elemental mercury (GEM) at our site. In addition, annual GOM dry deposition was approximately 1/2 of the average annual wet deposition of total mercury (7.7 ± 1.9 μg m(-2)year(-1)) at our site. Total annual mercury deposition from dry deposition of GOM and GEM and wet deposition was approximately 14.4 μg m(-2)year(-1), which was similar to the average annual litterfall deposition (15 ± 2.1 μg m(-2)year(-1)) of mercury, which was also measured at our site. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Absorption of gaseous iodine by water droplets

    International Nuclear Information System (INIS)

    Albert, M.F.

    1985-07-01

    A new model has been developed for predicting the rate at which gaseous molecular iodine is absorbed by water sprays. The model is a quasi-steady state mass transfer model that includes the iodine hydrolysis reactions. The parameters of the model are spray drop size, initial concentration of the gas and liquid phases, temperature, pressure, buffered or unbuffered spray solution, spray flow rate, containment diameter and drop fall height. The results of the model were studied under many values of these parameters. Plots of concentration of iodine species in the drop versus time have been produced by varying the initial gas phase concentration of molecular iodine over the range of 1 x 10 -5 moles/liter to 1 x 10 -10 moles/liter and a drop size of 1000 microns. Results from the model are compared to results available from Containment Systems Experiments at Pacific Northwest Laboratory. The difference between the model predictions and the experimental data ranges from -120.5% to 68.0% with the closest agreement 7.7%. The new spray model is also compared to previously existing spray models. At high concentrations of gaseous molecular iodine, the new spray model is considered to be less accurate but at low concentrations, the new model predicts results that are closer to the experimental data than the model called the realistic model from WASH-1329. Inclusion of the iodine hydrolysis reaction is shown to be a feature important to a model intended for determining the removal of molecular iodine over a wide range of conditions

  5. Liquefied Gaseous Fuels Spill Test Facility

    International Nuclear Information System (INIS)

    1993-02-01

    The US Department of Energy's liquefied Gaseous Fuels Spill Test Facility is a research and demonstration facility available on a user-fee basis to private and public sector test and training sponsors concerned with safety aspects of hazardous chemicals. Though initially designed to accommodate large liquefied natural gas releases, the Spill Test Facility (STF) can also accommodate hazardous materials training and safety-related testing of most chemicals in commercial use. The STF is located at DOE's Nevada Test Site near Mercury, Nevada, USA. Utilization of the Spill Test Facility provides a unique opportunity for industry and other users to conduct hazardous materials testing and training. The Spill Test Facility is the only facility of its kind for either large- or small-scale testing of hazardous and toxic fluids including wind tunnel testing under controlled conditions. It is ideally suited for test sponsors to develop verified data on prevention, mitigation, clean-up, and environmental effects of toxic and hazardous gaseous liquids. The facility site also supports structured training for hazardous spills, mitigation, and clean-up. Since 1986, the Spill Test Facility has been utilized for releases to evaluate the patterns of dispersion, mitigation techniques, and combustion characteristics of select materials. Use of the facility can also aid users in developing emergency planning under US P.L 99-499, the Superfund Amendments and Reauthorization Act of 1986 (SARA) and other regulations. The Spill Test Facility Program is managed by the US Department of Energy (DOE), Office of Fossil Energy (FE) with the support and assistance of other divisions of US DOE and the US Government. DOE/FE serves as facilitator and business manager for the Spill Test Facility and site. This brief document is designed to acquaint a potential user of the Spill Test Facility with an outline of the procedures and policies associated with the use of the facility

  6. Flux and polarization signals of spatially inhomogeneous gaseous exoplanets

    NARCIS (Netherlands)

    Karalidi, T.; Stam, D.M.; Guirado, D.

    2013-01-01

    Aims. We present numerically calculated, disk-integrated, spectropolarimetric signals of starlight that is reflected by vertically and horizontally inhomogeneous gaseous exoplanets. We include various spatial features that are present on Solar System’s gaseous planets: belts and zones, cyclonic

  7. Precision tracking with a single gaseous pixel detector

    NARCIS (Netherlands)

    Tsigaridas, S.; van Bakel, N.; Bilevych, Y.; Gromov, V.; Hartjes, F.; Hessey, N.P.; de Jong, P.; Kluit, R.

    2015-01-01

    The importance of micro-pattern gaseous detectors has grown over the past few years after successful usage in a large number of applications in physics experiments and medicine. We develop gaseous pixel detectors using micromegas-based amplification structures on top of CMOS pixel readout chips.

  8. Information system of quality assessment for liquid and gaseous medium production

    Science.gov (United States)

    Bobrov, V. N.; Us, N. A.; Davidov, I. S.

    2018-05-01

    A method and a technical solution for controlling the quality of production of liquid and gaseous media is proposed. It is also proposed to monitor harmful factors in production while ensuring safe working conditions. Initially, using the mathematical model of an ideal atmosphere, the projection to the horizontal surface of the observation trajectory is calculated. At the second stage, the horizontal projection of the observation trajectory in real conditions is measured. The quality of the medium is judged by the difference between the projections of observation trajectories. The technical result is presented in the form of a device allowing obtaining information about the quality of the medium under investigation.

  9. A numerical study on the characteristics of gaseous pollutant absorbed by a moving liquid aerosol

    International Nuclear Information System (INIS)

    Deng, J.J.; Du, Y.G.; Yu, Y.; Ding, J.

    2008-01-01

    Atmospheric pollution involving aerosols is becoming increasingly problematic. Since aerosols are small in size and have large specific surface areas, they can enhance some chemical reactions. Liquid aerosols in the air can absorb gaseous pollutants to adversely affect air quality and human health. This paper studied the characteristics of liquid aerosols and the absorption process of gaseous pollutants. Specifically, the paper presented a model to depict the characteristic of the absorption process of gaseous pollutant by a liquid aerosol with internal circulation and chemical reaction. The model assumed that liquid aerosols retain a spherical shape while moving freely in air. The finite volume method was used to develop an algorithm used to numerically simulate the experimental work of Walcek. The paper also discussed the numerical evaluation of the transient momentum and mass transfer characteristics of sulphur dioxide into a droplet. It was concluded that the chemical reaction increased the rate of mass transfer and the quasi-saturation time of aerosols, which provided a theoretical basis for the heterogeneous reaction of liquid aerosols. 3 refs., 6 figs

  10. Method and apparatus for the selective separation of gaseous coal gasification products by pressure swing adsorption

    Science.gov (United States)

    Ghate, M.R.; Yang, R.T.

    1985-10-03

    Bulk separation of the gaseous components of multi-component gases provided by the gasification of coal including hydrogen, carbon monoxide, methane, and acid gases (carbon dioxide plus hydrogen sulfide) are selectively adsorbed by a pressure swing adsorption technique using activated carbon zeolite or a combination thereof as the adsorbent. By charging a column containing the adsorbent with a gas mixture and pressurizing the column to a pressure sufficient to cause the adsorption of the gases and then reducing the partial pressure of the contents of the column, the gases are selectively and sequentially desorbed. Hydrogen, the least absorbable gas of the gaseous mixture, is the first gas to be desorbed and is removed from the column in a co-current direction followed by the carbon monoxide, hydrogen and methane. With the pressure in the column reduced to about atmospheric pressure the column is evacuated in a countercurrent direction to remove the acid gases from the column. The present invention is particularly advantageous as a producer of high purity hydrogen from gaseous products of coal gasification and as an acid gas scrubber. 2 figs., 2 tabs.

  11. Significance of population centers as sources of gaseous and dissolved PAHs in the lower Great Lakes.

    Science.gov (United States)

    McDonough, Carrie A; Khairy, Mohammed A; Muir, Derek C G; Lohmann, Rainer

    2014-07-15

    Polyethylene passive samplers (PEs) were used to measure concentrations of gaseous and dissolved polycyclic aromatic hydrocarbons (PAHs) in the air and water throughout the lower Great Lakes during summer and fall of 2011. Atmospheric Σ15PAH concentrations ranged from 2.1 ng/m3 in Cape Vincent (NY) to 76.4 ng/m3 in downtown Cleveland (OH). Aqueous Σ18PAH concentrations ranged from 2.4 ng/L at an offshore Lake Erie site to 30.4 ng/L in Sheffield Lake (OH). Gaseous PAH concentrations correlated strongly with population within 3-40 km of the sampling site depending on the compound considered, suggesting that urban centers are a primary source of gaseous PAHs (except retene) in the lower Great Lakes region. The significance of distant population (within 20 km) versus local population (within 3 km) increased with subcooled liquid vapor pressure. Most dissolved aqueous PAHs did not correlate significantly with population, nor were they consistently related to river discharge, wastewater effluents, or precipitation. Air-water exchange calculations implied that diffusive exchange was a source of phenanthrene to surface waters, while acenaphthylene volatilized out of the lakes. Comparison of air-water fluxes with temperature suggested that the significance of urban centers as sources of dissolved PAHs via diffusive exchange may decrease in warmer months.

  12. Methods for reformation of gaseous hydrocarbons using electrical discharge

    KAUST Repository

    Cha, Min Suk

    2017-02-16

    Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

  13. Methods for reformation of gaseous hydrocarbons using electrical discharge

    KAUST Repository

    Cha, Min; Zhang, Xuming

    2017-01-01

    Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

  14. Impact of the volume of gaseous phase in closed reactors on ANC results and modelling

    Science.gov (United States)

    Drapeau, Clémentine; Delolme, Cécile; Lassabatere, Laurent; Blanc, Denise

    2016-04-01

    The understanding of the geochemical behavior of polluted solid materials is often challenging and requires huge expenses of time and money. Nevertheless, given the increasing amounts of polluted solid materials and related risks for the environment, it is more and more crucial to understand the leaching of majors and trace metals elements from these matrices. In the designs of methods to quantify pollutant solubilization, the combination of experimental procedures with modeling approaches has recently gained attention. Among usual methods, some rely on the association of ANC and geochemical modeling. ANC experiments - Acid Neutralization Capacity - consists in adding known quantities of acid or base to a mixture of water and contaminated solid materials at a given liquid / solid ratio in closed reactors. Reactors are agitated for 48h and then pH, conductivity, redox potential, carbon, majors and heavy metal solubilized are quantified. However, in most cases, the amounts of matrix and water do not reach the total volume of reactors, leaving some space for air (gaseous phase). Despite this fact, no clear indication is given in standard procedures about the effect of this gaseous phase. Even worse, the gaseous phase is never accounted for when exploiting or modeling ANC data. The gaseous phase may exchange CO2 with the solution, which may, in turn, impact both pH and element release. This study lies within the most general framework for the use of geochemical modeling for the prediction of ANC results for the case of pure phases to real phase assemblages. In this study, we focus on the effect of the gaseous phase on ANC experiments on different mineral phases through geochemical modeling. To do so, we use PHREEQC code to model the evolution of pH and element release (including majors and heavy metals) when several matrices are put in contact with acid or base. We model the following scenarios for the gaseous phase: no gas, contact with the atmosphere (open system

  15. Atmospheric contamination

    International Nuclear Information System (INIS)

    Gruetter, Juerg

    1997-01-01

    It is about the levels of contamination in center America, the population's perception on the problem, effects of the atmospheric contamination, effects in the environment, causes of the atmospheric contamination, possibilities to reduce the atmospheric contamination and list of Roeco Swisscontac in atmospheric contamination

  16. Global evaluation and calibration of a passive air sampler for gaseous mercury

    Science.gov (United States)

    McLagan, David S.; Mitchell, Carl P. J.; Steffen, Alexandra; Hung, Hayley; Shin, Cecilia; Stupple, Geoff W.; Olson, Mark L.; Luke, Winston T.; Kelley, Paul; Howard, Dean; Edwards, Grant C.; Nelson, Peter F.; Xiao, Hang; Sheu, Guey-Rong; Dreyer, Annekatrin; Huang, Haiyong; Hussain, Batual Abdul; Lei, Ying D.; Tavshunsky, Ilana; Wania, Frank

    2018-04-01

    Passive air samplers (PASs) for gaseous mercury (Hg) were deployed for time periods between 1 month and 1 year at 20 sites across the globe with continuous atmospheric Hg monitoring using active Tekran instruments. The purpose was to evaluate the accuracy of the PAS vis-à-vis the industry standard active instruments and to determine a sampling rate (SR; the volume of air stripped of gaseous Hg per unit of time) that is applicable across a wide range of conditions. The sites spanned a wide range of latitudes, altitudes, meteorological conditions, and gaseous Hg concentrations. Precision, based on 378 replicated deployments performed by numerous personnel at multiple sites, is 3.6 ± 3.0 %1, confirming the PAS's excellent reproducibility and ease of use. Using a SR previously determined at a single site, gaseous Hg concentrations derived from the globally distributed PASs deviate from Tekran-based concentrations by 14.2 ± 10 %. A recalibration using the entire new data set yields a slightly higher SR of 0.1354 ± 0.016 m3 day-1. When concentrations are derived from the PAS using this revised SR the difference between concentrations from active and passive sampling is reduced to 8.8 ± 7.5 %. At the mean gaseous Hg concentration across the study sites of 1.54 ng m-3, this represents an ability to resolve concentrations to within 0.13 ng m-3. Adjusting the sampling rate to deployment specific temperatures and wind speeds does not decrease the difference in active-passive concentration further (8.7 ± 5.7 %), but reduces its variability by leading to better agreement in Hg concentrations measured at sites with very high and very low temperatures and very high wind speeds. This value (8.7 ± 5.7 %) represents a conservative assessment of the overall uncertainty of the PAS due to inherent uncertainties of the Tekran instruments. Going forward, the recalibrated SR adjusted for temperature and wind speed should be used, especially if conditions are highly variable or

  17. Global evaluation and calibration of a passive air sampler for gaseous mercury

    Directory of Open Access Journals (Sweden)

    D. S. McLagan

    2018-04-01

    Full Text Available Passive air samplers (PASs for gaseous mercury (Hg were deployed for time periods between 1 month and 1 year at 20 sites across the globe with continuous atmospheric Hg monitoring using active Tekran instruments. The purpose was to evaluate the accuracy of the PAS vis-à-vis the industry standard active instruments and to determine a sampling rate (SR; the volume of air stripped of gaseous Hg per unit of time that is applicable across a wide range of conditions. The sites spanned a wide range of latitudes, altitudes, meteorological conditions, and gaseous Hg concentrations. Precision, based on 378 replicated deployments performed by numerous personnel at multiple sites, is 3.6 ± 3.0 %1, confirming the PAS's excellent reproducibility and ease of use. Using a SR previously determined at a single site, gaseous Hg concentrations derived from the globally distributed PASs deviate from Tekran-based concentrations by 14.2 ± 10 %. A recalibration using the entire new data set yields a slightly higher SR of 0.1354 ± 0.016 m3 day−1. When concentrations are derived from the PAS using this revised SR the difference between concentrations from active and passive sampling is reduced to 8.8 ± 7.5 %. At the mean gaseous Hg concentration across the study sites of 1.54 ng m−3, this represents an ability to resolve concentrations to within 0.13 ng m−3. Adjusting the sampling rate to deployment specific temperatures and wind speeds does not decrease the difference in active–passive concentration further (8.7 ± 5.7 %, but reduces its variability by leading to better agreement in Hg concentrations measured at sites with very high and very low temperatures and very high wind speeds. This value (8.7 ± 5.7 % represents a conservative assessment of the overall uncertainty of the PAS due to inherent uncertainties of the Tekran instruments. Going forward, the recalibrated SR adjusted for temperature and wind speed

  18. Distribution of gaseous and particulate organic composition during dark α-pinene ozonolysis

    Directory of Open Access Journals (Sweden)

    A. R. Rickard

    2010-03-01

    Full Text Available Secondary Organic Aerosol (SOA affects atmospheric composition, air quality and radiative transfer, however major difficulties are encountered in the development of reliable models for SOA formation. Constraints on processes involved in SOA formation can be obtained by interpreting the speciation and evolution of organics in the gaseous and condensed phase simultaneously. In this study we investigate SOA formation from dark α-pinene ozonolysis with particular emphasis upon the mass distribution of gaseous and particulate organic species. A detailed model for SOA formation is compared with the results from experiments performed in the EUropean PHOtoREactor (EUPHORE simulation chamber, including on-line gas-phase composition obtained from Chemical-Ionization-Reaction Time-Of-Flight Mass-Spectrometry measurements, and off-line analysis of SOA samples performed by Ion Trap Mass Spectrometry and Liquid Chromatography. The temporal profile of SOA mass concentration is relatively well reproduced by the model. Sensitivity analysis highlights the importance of the choice of vapour pressure estimation method, and the potential influence of condensed phase chemistry. Comparisons of the simulated gaseous- and condensed-phase mass distributions with those observed show a generally good agreement. The simulated speciation has been used to (i propose a chemical structure for the principal gaseous semi-volatile organic compounds and condensed monomer organic species, (ii provide evidence for the occurrence of recently suggested radical isomerisation channels not included in the basic model, and (iii explore the possible contribution of a range of accretion reactions occurring in the condensed phase. We find that oligomer formation through esterification reactions gives the best agreement between the observed and simulated mass spectra.

  19. Modeling dynamic exchange of gaseous elemental mercury at polar sunrise.

    Science.gov (United States)

    Dastoor, Ashu P; Davignon, Didier; Theys, Nicolas; Van Roozendael, Michel; Steffen, Alexandra; Ariya, Parisa A

    2008-07-15

    At polar sunrise, gaseous elemental mercury (GEM) undergoes an exceptional dynamic exchange in the air and at the snow surface during which GEM can be rapidly removed from the atmosphere (the so-called atmospheric mercury depletion events (AMDEs)) as well as re-emitted from the snow within a few hours to days in the Polar Regions. Although high concentrations of total mercury in snow following AMDEs is well documented, there is very little data available on the redox transformation processes of mercury in the snow and the fluxes of mercury at the air/snow interface. Therefore, the net gain of mercury in the Polar Regions as a result of AMDEs is still an open question. We developed a new version of the global mercury model, GRAHM, which includes for the first time bidirectional surface exchange of GEM in Polar Regions in spring and summer by developing schemes for mercury halogen oxidation, deposition, and re-emission. Also for the first time, GOME satellite data-derived boundary layer concentrations of BrO have been used in a global mercury model for representation of halogen mercury chemistry. Comparison of model simulated and measured atmospheric concentrations of GEM at Alert, Canada, for 3 years (2002-2004) shows the model's capability in simulating the rapid cycling of mercury during and after AMDEs. Brooks et al. (1) measured mercury deposition, reemission, and net surface gain fluxes of mercury at Barrow, AK, during an intensive measurement campaign for a 2 week period in spring (March 25 to April 7, 2003). They reported 1.7, 1.0 +/- 0.2, and 0.7 +/- 0.2 microg m(-2) deposition, re-emission, and net surface gain, respectively. Using the optimal configuration of the model, we estimated 1.8 microg m(-2) deposition, 1.0 microg m(-2) re-emission, and 0.8 microg m(-2) net surface gain of mercury for the same time period at Barrow. The estimated net annual accumulation of mercury within the Arctic Circle north of 66.5 degrees is approximately 174 t with +/-7 t of

  20. Production of jet fuel range paraffins by low temperature polymerization of gaseous light olefins using ionic liquid

    International Nuclear Information System (INIS)

    Jiang, Peiwen; Wu, Xiaoping; Zhu, Lijuan; Jin, Feng; Liu, Junxu; Xia, Tongyan; Wang, Tiejun; Li, Quanxin

    2016-01-01

    Graphical abstract: A novel catalytic transformation of light olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. - Highlights: • A novel transformation of light olefins to jet fuel range paraffins was demonstrated. • The synthetic fuels can be produced by atmospheric olefin polymerizations. • C 8 –C 15 iso-paraffins from light olefins was achieved with a selectivity of 80.6%. - Abstract: This work demonstrated a novel catalytic transformation of gaseous olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. The production of the desired C 8 –C 15 iso-paraffins with the selectivity of 80.6 C mol% was achieved by the room-temperature polymerizations of gaseous light olefins using the [BMIM] Al 2 Cl 7 ionic liquid. The influences of the reaction conditions on the olefinic polymerizations were investigated in detail. The properties of hydrocarbons in the synthetic fuels were determined by the GC–MS analyses combined with 1 H NMR, and 13 C NMR analyses. The formation of C 8 –C 15 hydrocarbons from gaseous light olefins was illustrated by the identified products and the functional groups. This transformation potentially provides a useful avenue for the production of the most important components of iso-paraffins required in jet fuels.

  1. Gaseous isotope correlation technique for safeguards at reprocessing facilities

    International Nuclear Information System (INIS)

    Ohkubo, Michiaki.

    1988-03-01

    The isotope correlation technique based on gaseous stable fission products can be used as a means of verifying the input measurement to fuel reprocessing plants. This paper reviews the theoretical background of the gaseous fission product isotope correlation technique. The correlations considered are those between burnup and various isotopic ratios of Kr and Xe nuclides. The feasibility of gaseous ICT application to Pu input accountancy of reprocessing facilities is also discussed. The technique offers the possibility of in situ measurement verification by the inspector. (author). 16 refs, 7 figs

  2. Growth of graphene films from non-gaseous carbon sources

    Science.gov (United States)

    Tour, James; Sun, Zhengzong; Yan, Zheng; Ruan, Gedeng; Peng, Zhiwei

    2015-08-04

    In various embodiments, the present disclosure provides methods of forming graphene films by: (1) depositing a non-gaseous carbon source onto a catalyst surface; (2) exposing the non-gaseous carbon source to at least one gas with a flow rate; and (3) initiating the conversion of the non-gaseous carbon source to the graphene film, where the thickness of the graphene film is controllable by the gas flow rate. Additional embodiments of the present disclosure pertain to graphene films made in accordance with the methods of the present disclosure.

  3. Coevolution of Binaries and Circumbinary Gaseous Disks

    Science.gov (United States)

    Fleming, David; Quinn, Thomas R.

    2018-04-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disk, and how the disk and binary interact. The central binary excites resonances in the surrounding protoplanetary disk that drive evolution in both the binary orbital elements and in the disk. To probe how these interactions impact both binary eccentricity and disk structure evolution, we ran N-body smooth particle hydrodynamics (SPH) simulations of gaseous protoplanetary disks surrounding binaries based on Kepler 38 for 10^4 binary orbital periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disk via a parametric instability and excite disk eccentricity growth. Eccentric binaries strongly couple to the disk causing eccentricity growth for both the disk and binary. Disks around sufficiently eccentric binaries strongly couple to the disk and develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance (EOLR). This wave corresponds to an alignment of gas particle longitude of periastrons. We find that in all simulations, the binary semi-major axis decays due to dissipation from the viscous disk.

  4. Method for separating gaseous mixtures of matter

    International Nuclear Information System (INIS)

    Schuster, E.; Kersting, A.

    1979-01-01

    Molecules to be separated from a mixture of matter of a chemical component are excited in a manner known per se by narrow-band light sources, and a chemical reaction partner for reacting with these molecules is admixed while supplied with energy by electromagnetic radiation or heating, and as additionally required for making chemical reactions possible. A method is described for separating gaseous mixtures of matter by exciting the molecules to be separated with laser radiation and causing the excited species to react chemically with a reaction partner. It may be necessary to supply additional energy to the reaction partner to make the chemical reaction possible. The method is applicable to the separation of hydrogen isotopes by the bromination of normal methanol in a mixture normal methanol and deuterated methanol; of uranium isotope by the reactions of UF 6 with SF 4 , SiCl 4 , HCl, or SO 2 ; and of boron isotopes by the reaction of BH 3 with NH 3

  5. Gaseous Nitrogen Orifice Mass Flow Calculator

    Science.gov (United States)

    Ritrivi, Charles

    2013-01-01

    The Gaseous Nitrogen (GN2) Orifice Mass Flow Calculator was used to determine Space Shuttle Orbiter Water Spray Boiler (WSB) GN2 high-pressure tank source depletion rates for various leak scenarios, and the ability of the GN2 consumables to support cooling of Auxiliary Power Unit (APU) lubrication during entry. The data was used to support flight rationale concerning loss of an orbiter APU/hydraulic system and mission work-arounds. The GN2 mass flow-rate calculator standardizes a method for rapid assessment of GN2 mass flow through various orifice sizes for various discharge coefficients, delta pressures, and temperatures. The calculator utilizes a 0.9-lb (0.4 kg) GN2 source regulated to 40 psia (.276 kPa). These parameters correspond to the Space Shuttle WSB GN2 Source and Water Tank Bellows, but can be changed in the spreadsheet to accommodate any system parameters. The calculator can be used to analyze a leak source, leak rate, gas consumables depletion time, and puncture diameter that simulates the measured GN2 system pressure drop.

  6. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  7. Automated sampling and control of gaseous simulations

    KAUST Repository

    Huang, Ruoguan

    2013-05-04

    In this work, we describe a method that automates the sampling and control of gaseous fluid simulations. Several recent approaches have provided techniques for artists to generate high-resolution simulations based on a low-resolution simulation. However, often in applications the overall flow in the low-resolution simulation that an animator observes and intends to preserve is composed of even lower frequencies than the low resolution itself. In such cases, attempting to match the low-resolution simulation precisely is unnecessarily restrictive. We propose a new sampling technique to efficiently capture the overall flow of a fluid simulation, at the scale of user\\'s choice, in such a way that the sampled information is sufficient to represent what is virtually perceived and no more. Thus, by applying control based on the sampled data, we ensure that in the resulting high-resolution simulation, the overall flow is matched to the low-resolution simulation and the fine details on the high resolution are preserved. The samples we obtain have both spatial and temporal continuity that allows smooth keyframe matching and direct manipulation of visible elements such as smoke density through temporal blending of samples. We demonstrate that a user can easily configure a simulation with our system to achieve desired results. © 2013 Springer-Verlag Berlin Heidelberg.

  8. GEM - A novel gaseous particle detector

    CERN Document Server

    Meinschad, T

    2005-01-01

    The work carried out within the framework of this Ph.D. deals with the construction of gaseous prototype detectors using Gas Electron Multiplier electrodes for the amplification of charges released by ionizing particles. The Gas Electron Multiplier (GEM) is a thin metal-clad polymer foil, etched with a high density of narrow holes, typically 50-100mm-2. On the application of a potential difference between the conductive top and bottom sides each hole acts as independent proportional counter. This new fast device permits to reach large amplification factors at high rates with a strong photon and ion-mediated feedback suppression due to the avalanche confinement in the GEM-holes. Here, in particular studies have been performed, which should prove, that the GEM-technology is applicable for an efficient measurement of single Cherenkov photons. These UV-photons can be detected in different ways. An elegant solution to develop large area RICH-detectors is to evaporate a pad-segmented readout-cathode of a multi-wire...

  9. Inflammability of magnesium and its alloys in carbon dioxide either pure or mixed with water vapour, air or oxygen; Inflammabilite du magnesium et de ses alliages dans le gaz carbonique et ses melanges avec la vapeur d'eau, l'air ou l'oxygene

    Energy Technology Data Exchange (ETDEWEB)

    Baque, P; Chevilliard, C; Darras, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Whereas low contents of metallic additions have only a small influence on the temperature at which magnesium begins to burn in carbon dioxide, an increase in the specific surface area of the samples is likely to reduce it considerably, the self-heating phenomena being then more pronounced. On the other hand, the exact nature of the surrounding atmosphere is a very important factor; thus the temperature at which ignition begins increases with increasing carbon dioxide pressure, decreases very rapidly when the moisture content of this gas increases up to 3000 v.p.m., and decreases regularly when the partial pressure of air or oxygen increases. (authors) [French] Alors que de faibles teneurs en additions metalliques n'ont que peu d'influence sur la temperature d'inflammation du magnesium dans le gaz carbonique, l'augmentation de la surface specifique des echantillons est susceptible de l'abaisser fortement, le phenomene d'autochauffage se trouvant alors accru. D'autre part, la nature exacte de l'atmosphere gazeuse ambiante est un facteur tres important; ainsi la temperature d'inflammation croit avec la pression du gaz carbonique, decroit tres rapidement lorsque sa teneur en humidite augmente jusqu'a 3000 v.p.m., et diminue regulierement lorsque la pression partielle d'air ou d'oxygene augmente. (auteurs)

  10. Mass spectrometric study of thermodynamic properties of gaseous lead tellurates. Estimation of formation enthalpies of gaseous lead polonates

    Energy Technology Data Exchange (ETDEWEB)

    Shugurov, S.M., E-mail: s.shugurov@spbu.ru; Panin, A.I.; Lopatin, S.I.; Emelyanova, K.A.

    2016-10-15

    Gaseous reactions involving lead oxides, tellurium oxide and lead tellurates were studied by the Knudsen effusion mass spectrometry. Equilibrium constants and reaction enthalpies were evaluated. Structures, molecular parameters and thermodynamic functions of gaseous PbTeO{sub 3} and Pb{sub 2}TeO{sub 4} were calculated by quantum chemistry methods. The formation enthalpies Δ{sub f}H{sup 0} (298.15) = −294 ± 13 for gaseous PbTeO{sub 3} and Δ{sub f}H{sup 0} (298.15) = −499 ± 12 for gaseous Pb{sub 2}TeO{sub 4} were obtained. On the base of these results the formation enthalpies of gaseous PbPoO{sub 3} and Pb{sub 2}PoO{sub 4} were estimated as −249 ± 34 and −478 ± 38, respectively. - Highlights: • Gaseous lead tellurates PbTeO{sub 3}, Pb{sub 2}TeO{sub 4} were discovered. • Their thermodynamic properties were studied using both high temperature mass spectrometry and quantum chemistry computations. • The obtained data allows to predict the formation enthalpies of gaseous lead polonates PbPoO{sub 3}, Pb{sub 2}PoO{sub 4}.

  11. Clouds in the Martian Atmosphere

    Science.gov (United States)

    Määttänen, Anni; Montmessin, Franck

    2018-01-01

    Although resembling an extremely dry desert, planet Mars hosts clouds in its atmosphere. Every day somewhere on the planet a part of the tiny amount of water vapor held by the atmosphere can condense as ice crystals to form cirrus-type clouds. The existence of water ice clouds has been known for a long time, and they have been studied for decades, leading to the establishment of a well-known climatology and understanding of their formation and properties. Despite their thinness, they have a clear impact on the atmospheric temperatures, thus affecting the Martian climate. Another, more exotic type of clouds forms as well on Mars. The atmospheric temperatures can plunge to such frigid values that the major gaseous component of the atmosphere, CO2, condenses as ice crystals. These clouds form in the cold polar night where they also contribute to the formation of the CO2 ice polar cap, and also in the mesosphere at very high altitudes, near the edge of space, analogously to the noctilucent clouds on Earth. The mesospheric clouds are a fairly recent discovery and have put our understanding of the Martian atmosphere to a test. On Mars, cloud crystals form on ice nuclei, mostly provided by the omnipresent dust. Thus, the clouds link the three major climatic cycles: those of the two major volatiles, H2O and CO2; and that of dust, which is a major climatic agent itself.

  12. Two new sources of reactive gaseous mercury in the free troposphere

    Science.gov (United States)

    Timonen, H.; Ambrose, J. L.; Jaffe, D. A.

    2012-11-01

    Mercury (Hg) is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM) generates reactive gaseous mercury (RGM) which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the sources and chemical composition of RGM are poorly known. Using speciated mercury measurements conducted at the Mt. Bachelor Observatory since 2005 we present two previously unidentified sources of RGM to the free troposphere (FT). Firstly, we observed elevated RGM concentrations, large RGM/GEM-ratios, and anti-correlation between RGM and GEM during Asian long-rang transport events, demonstrating that RGM is formed from GEM by in-situ oxidation in some anthropogenic pollution plumes in the FT. During the Asian pollution events the measured RGM/GEM-ratios reached peak values, up to ~0.20, which are significantly larger than ratios typically measured (RGM/GEM RGM levels - the highest reported in the FT - in clean air masses that were processed upwind of Mt. Bachelor Observatory over the Pacific Ocean. The high RGM concentrations (up to 700 pg m-3), high RGM/GEM-ratios (up to 1), and very low ozone levels during these events provide the first observational evidence indicating significant GEM oxidation in the lower FT. The identification of these processes changes our conceptual understanding of the formation and distribution of oxidized Hg in the global atmosphere.

  13. Container for gaseous samples for irradiation at accelerators

    International Nuclear Information System (INIS)

    Kupsch, H.; Riemenschneider, J.; Leonhardt, J.

    1985-01-01

    The invention concerns a container for gaseous samples for the irradiation at accelerators especially to generate short-lived radioisotopes. The container is also suitable for storage and transport of the target gas and can be multiply reused

  14. Sampling and identification of gaseous and particle bounded air pollutants

    International Nuclear Information System (INIS)

    Kettrup, A.

    1993-01-01

    Air pollutants are gaseous, components of aerosols or particle bounded. Sampling, sample preparation, identification and quantification of compounds depend from kind and chemical composition of the air pollutants. Quality assurance of analytical data must be guaranted. (orig.) [de

  15. Device for taking gaseous samples from irradiated fuel elements

    International Nuclear Information System (INIS)

    Lengacker, B.

    1983-01-01

    The described device allows to take gaseous samples from irradiated fuel elements. It is connected with a gas analyzer and a pressure gage, so that in opening the fuel can the internal pressure can be determined

  16. Astrophysics of gaseous nebulae and active galactic nuclei

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1989-01-01

    A graduate-level text and reference book on gaseous nebulae and the emission regions in Seyfert galaxies, quasars, and other types of active galactic nuclei (AGN) is presented. The topics discussed include: photoionization equilibrium, thermal equilibrium, calculation of emitted spectrum, comparison of theory with observations, internal dynamics of gaseous nebulae, interstellar dust, regions in the galactic context, planetary nebulae, nova and supernova remnants, diagnostics and physics of AGN, observational results on AGN

  17. Freezer-sublimer for gaseous diffusion plant

    International Nuclear Information System (INIS)

    Reti, G.R.

    1978-01-01

    A method and apparatus is disclosed for freezing and subliming uranium hexafluoride (UF 6 ) as part of a gaseous diffusion plant from which a quantity of the UF 6 inventory is intermittently withdrawn and frozen to solidify it. A plurality of upright heat pipes holds a coolant and is arranged in a two compartment vessel, the lower compartment is exposed to UF 6 , the higher one serves for condensing the evaporated coolant by means of cooling water. In one embodiment, each pipe has a quantity of coolant such as freon, hermetically sealded therein. In the other embodiment, each pipe is sealed only at the lower end while the upper end communicates with a common vapor or cooling chamber which contains a water cooled condenser. The cooling water has a sufficiently low temperature to condense the evaporated coolant. The liquid coolant flows gravitationally downward to the lower end portion of the pipe. UF 6 gas is flowed into the tank where it contacts the finned outside surface of the heat pipes. Heat from the gas evaporates the coolant and the gas in turn is solidified on the exterior of the heat pipe sections in the tank. To recover UF 6 gas from the tank, the solidified UF 6 is sublimed by passing compressed UF 6 gas over the frozen UF 6 gas on the pipes or by externally heating the lower ends of the pipes sufficiently to evaporate the coolant therein above the subliming temperature of the UF 6 . The subliming UF 6 gas then condenses the coolant in the vertical heat pipes, so that it can gravitationally flow back to the lower end portions

  18. Euthanasia using gaseous agents in laboratory rodents.

    Science.gov (United States)

    Valentim, A M; Guedes, S R; Pereira, A M; Antunes, L M

    2016-08-01

    Several questions have been raised in recent years about the euthanasia of laboratory rodents. Euthanasia using inhaled agents is considered to be a suitable aesthetic method for use with a large number of animals simultaneously. Nevertheless, its aversive potential has been criticized in terms of animal welfare. The data available regarding the use of carbon dioxide (CO2), inhaled anaesthetics (such as isoflurane, sevoflurane, halothane and enflurane), as well as carbon monoxide and inert gases are discussed throughout this review. Euthanasia of fetuses and neonates is also addressed. A table listing currently available information to ease access to data regarding euthanasia techniques using gaseous agents in laboratory rodents was compiled. Regarding better animal welfare, there is currently insufficient evidence to advocate banning or replacing CO2 in the euthanasia of rodents; however, there are hints that alternative gases are more humane. The exposure to a volatile anaesthetic gas before loss of consciousness has been proposed by some scientific studies to minimize distress; however, the impact of such a measure is not clear. Areas of inconsistency within the euthanasia literature have been highlighted recently and stem from insufficient knowledge, especially regarding the advantages of the administration of isoflurane or sevoflurane over CO2, or other methods, before loss of consciousness. Alternative methods to minimize distress may include the development of techniques aimed at inducing death in the home cage of animals. Scientific outcomes have to be considered before choosing the most suitable euthanasia method to obtain the best results and accomplish the 3Rs (replacement, reduction and refinement). © The Author(s) 2015.

  19. Treatment of Plants with Gaseous Ethylene and Gaseous Inhibitors of Ethylene Action.

    Science.gov (United States)

    Tucker, Mark L; Kim, Joonyup; Wen, Chi-Kuang

    2017-01-01

    The gaseous nature of ethylene affects not only its role in plant biology but also how you treat plants with the hormone. In many ways, it simplifies the treatment problem. Other hormones have to be made up in solution and applied to some part of the plant hoping the hormone will be taken up into the plant and translocated throughout the plant at the desired concentration. Because all plant cells are connected by an intercellular gas space the ethylene concentration you treat with is relatively quickly reached throughout the plant. In some instances, like mature fruit, treatment with ethylene initiates autocatalytic synthesis of ethylene. However, in most experiments, the exogenous ethylene concentration is saturating, usually >1 μL L -1 , and the synthesis of additional ethylene is inconsequential. Also facilitating ethylene research compared with other hormones is that there are inhibitors of ethylene action 1-MCP (1-methylcyclopropene) and 2,5-NBD (2,5-norbornadiene) that are also gases wherein you can achieve nearly 100% inhibition of ethylene action quickly and with few side effects. Inhibitors for other plant hormones are applied as a solution and their transport and concentration at the desired site is not always known and difficult to measure. Here, our focus is on how to treat plants and plant parts with the ethylene gas and the gaseous inhibitors of ethylene action.

  20. Method of separating tritium contained in gaseous wastes

    International Nuclear Information System (INIS)

    Hashimoto, Yasuo; Oozono, Hideaki.

    1981-01-01

    Purpose: To decrease tritium concentration in gaseous wastes to less than the allowable level by removing tritium in gaseous wastes generated upon combustion of radioactive wastes by using a plurality of heat exchangers. Method: Gaseous wastes at high temperature generated upon combustion of radioactive wastes in an incinerator are removed with radioactive solid substances through filters, cooled down to a temperature below 10 0 C by the passage through first and second heat exchangers and decreased with tritium content to less than the allowable concentration by the gaseous wastes at low temperature from the second heat exhcanger. The gaseous wastes at low temperature are used as the cooling medium for the first heat exchanger. They are heat exchanged at the upstream of the second heat exchanger with the cooling water from the third heat exchanger and cooled at the downstream by the cooling water cooled by the cooling medium. The gaseous wastes at low temperature thus cooled below 10 0 C are heated to about 350 0 C in the first heat exchanger and discharged. (Moriyama, K.)

  1. Decrease of the atmospheric co-rotation with height

    International Nuclear Information System (INIS)

    Membrado, M; Pacheco, A F

    2010-01-01

    Considering our atmosphere as a steady viscous gaseous envelope that co-rotates with the Earth, we obtain a solution for the form in which this induced rotational effect decreases as a function of the distances to the centre of the Earth and to the rotation axis.

  2. Atmospheric ventilation corridors and coefficients for pollution plume ...

    African Journals Online (AJOL)

    This study presents a comparative investigation of atmospheric ventilation corridors and coefficients for gaseous pollution plume released from an isolated industrial facility into the ambient air of the host community in Ile-Ife suburb, southwest Nigeria. For the months of September to December in the year 2012 and 2013, ...

  3. Surface - atmosphere exchange of ammonia over grazed pasture

    NARCIS (Netherlands)

    Plantaz, M.A.H.G.

    1998-01-01

    This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.
    Ammonia exchange

  4. Changes in oxidative potential of soil and fly ash after reaction with gaseous nitric acid

    Science.gov (United States)

    Zhan, Ying; Ginder-Vogel, Matthew; Shafer, Martin M.; Rudich, Yinon; Pardo, Michal; Katra, Itzhak; Katoshevski, David; Schauer, James J.

    2018-01-01

    The goal of this study was to examine the impact of simulated atmospheric aging on the oxidative potential of inorganic aerosols comprised primarily of crustal materials. Four soil samples and one coal fly ash sample were artificially aged in the laboratory through exposure to the vapor from 15.8 M nitric acid solution for 24 h at room temperature. Native and acid-aged samples were analyzed with a cellular macrophage and acellular dithionthreitol assays to determine oxidative potential. Additionally, the samples were analyzed to determine the concentration of 50 elements, both total and the water-soluble fraction of these elements by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICMS) and crystalline mineral composition using X-ray Diffraction (XRD). The results show that reactions with gaseous nitric acid increase the water-soluble fraction of many elements, including calcium, iron, magnesium, zinc, and lead. The mineral composition analysis documented that calcium-rich minerals present in the soils (e.g., calcite) are converted into different chemical forms, such as calcium nitrate (Ca(NO3)2). The nitric acid aging process, which can occur in the atmosphere, leads to a 200-600% increase in oxidative potential, as measured by cellular and acellular assays. This laboratory study demonstrates that the toxic effects of aged versus freshly emitted atmospheric dust may be quite different. In addition, the results suggest that mineralogical analysis of atmospheric dust may be useful in understanding its degree of aging.

  5. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Elliot, J.L.; Dunham, E.W.; Bosh, A.S.; Slivan, S.M.; Young, L.A.

    1989-01-01

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  6. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  7. The greenhouse effect of planetary atmospheres

    International Nuclear Information System (INIS)

    Kondratyev, K.Ya.; Moskalenko, N.I.

    1980-01-01

    The greenhouse effect of the atmosphere is the main factor of possible climate changes of anthropogenic origin. The growing pollution of the atmosphere leads to an increase of the concentration of various gaseous components. Of great importance is also the consideration of the aerosols. All the gaseous components, as well as aerosols, have the absorption bands in the IR spectral range. The traditional attention to the problem of the CO 2 contribution to the greenhouse effect has somewhat overshadowed the significance of the different components. The data characterizing the significance of the different components of the greenhouse effect are considered. The results of studying the absorption spectra of methane, nitrous oxides, sulphuric gas, ammonia, nitric-acid vapours and other components are discussed. The assessments of their contribution to the greenhouse effect are given. The important role of the small-size fraction of the atmospheric aerosols as a factor of the greenhouse effect is discussed. Both the analysis of the causes of the Earth's climate variability and the relevant investigation of the atmospheric greenhouse effect determine the expediency of analysing the conditions of the greenhouse effect formation on other planets. Laboratory studies of the IR absorption spectra of synthetic CO 2 atmospheres were carried out. Some results from these studies are discussed. (author)

  8. Seasonal and diurnal variation in concentrations of gaseous and particulate phase endosulfan

    Science.gov (United States)

    Li, Qingbo; Wang, Xianyu; Song, Jing; Sui, Hongqi; Huang, Lei; Li, Lu

    2012-12-01

    Successive 52-week air monitoring of α-endosulfan (α-E), β-endosulfan (β-E) and endosulfan sulfate (E.S) in the gaseous and particulate phases was conducted in Dalian city, northeast China by using an active high-volume sampler. Significant seasonal and diurnal variations in endosulfan concentrations were observed. It was found that the concentration of gaseous-phase α-E peaked in the summer and the concentration of particulate phase α-E peaked in the winter. For E.S, both gaseous and particulate phase concentrations peaked in the summer. α-E was distributed predominantly in the gas phase in the summer but was distributed mainly in the particulate phase in the winter. β-E was distributed mainly in the gas phase in the summer and in the particulate phase at other times of the year. E.S was distributed mainly in the particulate phase throughout the year. Elevated temperatures facilitated the volatilization of α-E from particle surfaces but exerted little effect on β-E and had almost no effect on E.S. Trajectory-based analysis indicates that the seasonal variation in atmospheric concentrations of endosulfan in Dalian city was influenced strongly by the land and sea air masses. In addition, differences in endosulfan concentrations in the particulate phase between day and night were likely due to the circulation of sea/land breezes. The 'cold-condensation' effect occurring during the night may result in the attachment of endosulfan to the particulate phase.

  9. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...

  10. Atmospheric electrodynamics

    International Nuclear Information System (INIS)

    Volland, H.

    1984-01-01

    The book Atmospheric Electrodynamics, by Hans Voland is reviewed. The book describes a wide variety of electrical phenomena occurring in the upper and lower atmosphere and develops the mathematical models which simulate these processes. The reviewer finds that the book is of interest to researchers with a background in electromagnetic theory but is of only limited use as a reference work

  11. Urban atmospheres.

    Science.gov (United States)

    Gandy, Matthew

    2017-07-01

    What is an urban atmosphere? How can we differentiate an 'atmosphere' from other facets of urban consciousness and experience? This essay explores some of the wider cultural, political, and philosophical connotations of atmospheres as a focal point for critical reflections on space and subjectivity. The idea of an 'affective atmosphere' as a distinctive kind of mood or shared corporeal phenomenon is considered in relation to recent developments in phenomenology, extended conceptions of agency, and new understandings of materialism. The essay draws in particular on the changing characteristics of air and light to reflect on different forms of sensory experience and their wider cultural and political connotations. The argument highlights some of the tensions and anomalies that permeate contemporary understandings of urban atmospheres.

  12. CARIBIC observations of gaseous mercury in the upper troposphere and lower stratosphere

    Directory of Open Access Journals (Sweden)

    Slemr F.

    2013-04-01

    Full Text Available A unique set of gaseous mercury measurements in the upper troposphere and lower stratosphere (UT/LS has been obtained during the monthly CARIBIC (www.caribic-atmospheric.com flights since May 2005. The passenger Airbus 340-600 of Lufthansa covered routes to the Far East, North America, India, and the southern hemisphere. The accompanying measurements of CO, O3, NOy, H2O, aerosols, halocarbons, hydrocarbons, greenhouse gases, and several other parameters as well as backward trajectories enable a detailed analysis of these measurements. Speciation tests have shown that the CARIBIC measurements represent a good approximation of total gaseous mercury (TGM concentrations. Above the tropopause TGM always decrease with increasing potential vorticity (PV and O3 which implies its conversion to particle bound mercury. The observation of the lowest TGM concentrations at the highest particle concentrations in the stratosphere provides further evidence for such conversion. We will show how a seasonally dependent conversion rate could be derived using concomitantly measured SF6 mixing ratios as a timer. Tropospheric mercury data suggest the existence of a decreasing trend in the northern hemisphere whose size is comparable with the trend derived from long-term measurements by ship cruises, at Cape Point (South Africa and Mace Head (Ireland.

  13. Gaseous environment of plants and activity of enzymes of carbohydrate catabolism

    International Nuclear Information System (INIS)

    Ivanov, B.F.; Zemlyanukhin, A.A.; Igamberdiev, A.U.; Salam, A.M.M.

    1989-01-01

    The authors investigated the action of hypoxia and high CO 2 concentration in the atmosphere on activity of phosphofructokinase, aldolase, glucose phosphate isomerase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, and isocitrate lyase in pea seedlings (Pisum sativum L.), corn scutella (Zea mays L.), and hemp cotyledons (Cannabis sativa L.). The first 4-12h of hypoxia witnessed suppression of enzymes of the initial stages of glycolysis (glucose-6-phosphate isomerase, phosphofructokinase)and activation of enzymes of its final stages (alcohol dehydrogenase and lactate dehydrogenase) and enzymes linking glycolysis and the pentose phosphate pathway (aldolase and glucose-6-phosphate dehydrogenase). An excess of CO 2 in the environment accelerated and amplified this effect. At the end of a 24-h period of anaerobic incubation, deviations of enzyme activity from the control were leveled in both gaseous environments. An exception was observed in the case of phosphofructokinase, whose activity increased markedly at this time in plants exposed to CO 2 . Changes in activity of the enzymes were coupled with changes in their kinetic parameters (apparent K m and V max values). The activity of isocitrate lyase was suppressed in both variants of hypoxic gaseous environments, a finding that does not agree with the hypothesis as to participation of the glyoxylate cycle in the metabolic response of plants to oxygen stress. Thus, temporary inhibition of the system of glycolysis and activation of the pentose phosphate pathway constituted the initial response of the plants to O 2 stress, and CO 2 intensified this metabolic response

  14. Preliminary study of the distribution of gaseous mercury species in the air of Guiyang city, China

    Science.gov (United States)

    Shang, L.; Feng, X.; Zheng, W.; Yan, H.

    2003-05-01

    Total gaseous mercury (TGM) in ambient air consists of Hg^0 and reactive gaseous mercury (RGM) in general. Although RGM only constitutes a small portion of TGM in the air, it contributes the most to both dry and wet deposition of mercury from the atmosphere. TGM and RGM concentrations in ambient air at one site of Guiyang City were determined in March 2002. TGM concentrations were monitored using an automated mercury vapor analyzer Tekran2537A, and RGM in ambient air was sampled using KCI coated tubular denuders. The sampled RGM denuders were analyzed using thermal desorption coupled with CVAFS detection. The average concentrations of TGM and RGM are 7.09 ng m^{-3} and 37.5pg m^{-3} respectively during the sampling period. The primary anthropogenic source for both Hg^0 and RGM is coal combustion in the study area. TGM concentrations are significantly elevated comparing to the global background values, whereas RGM concentrations are only slightly higher than the reported values in remote areas in Europe and US. RGM only constitutes 0.5% ofTGM in the air at the sampling period. There is a significant negative correlation between RGM concentration and relative humidity (RH), with a coefficient correlation of 0.39 (αRGM concentrations observed.

  15. Portsmouth Gaseous Diffusion Plant environmental monitoring report for calendar year 1981

    International Nuclear Information System (INIS)

    Acox, T.A.; Anderson, R.E.; Hary, L.F.; Klein, L.S.; Vausher, A.L.

    1982-04-01

    At the Portsmouth Gaseous Diffusion Plant all effluent streams are sampled regularly and analyzed to assess compliance with applicable environmental standards. Radioactivity is measured in air, water, food, soil, and sediments; and radiation doses to the public are calculated. All public radiation doses from process effluents are well within Department of Energy and US EPA standards. Non-radioactive effluents either presently comply with federal standards or will comply upon completion of planned projects. The environmental impact of effluents from cleaning and decontamination operations has been reduced through flow reduction and improved chemical treatment. CY-1981 was the first full year under a new National Pollutant Discharge. Elimination System (NPDES) permit for liquid effluents; compliance with the permit's discharge limits did not present any significant problems. Engineering is proceeding on projects to be constructed through 1985 to further reduce the impact of liquid effluents. A new licensed sanitary landfill utilizing the area fill method went into operation in July 1981. Although neither the State of Ohio nor the federal government has established standards for fluoride in the atmosphere or in vegetation, fluorides are monitored because they are used extensively in the gaseous diffusion process

  16. Gaseous products and smoke generation on combustion of the insulation materials of nuclear cables

    International Nuclear Information System (INIS)

    Noguchi, Isamu; Takami, Hiroshi; Ueyama, Michio; Fujimura, Shun-ichi.

    1976-01-01

    Serious requirements have been introduced to the cables used for nuclear power plants on their flame retardation in the IEEE Standard 383-1974. The movements that the users prescribe the quantity of corrosive gas generated from cables are also observed. This report describes on the measured results of the gaseous products generated by burning polyethylene, polyvinyl-chloride (PVC) and their flame-resistant products, and a part of the covering materials of the cables for nuclear power plants (flame-resistant, crosslinking polyethylene, flame-resistant, low hydrochloric acid PVC, flame-resistant jute) in the infra-red rapid heating combustion test facility designed by the Furukawa Electric Co. Ltd. In addition, the report introduces the test method for the smoke generation evaluation of polymers and a part of the measured results. The gaseous products of combustion were collected and determined quantitatively by gas chromatographic method. Since smoke generation is affected greatly by the kinds, shape, atmosphere, temperature, ignition procedure and others of burnt matters, the establishment of the evaluation test method is difficult, and a number of methods have been proposed. As the measured results showed, it is clear that smoke generation increases with the increase of flame resistant reagent addition. The smoke generation of PVC was of course great in quantity because it contains considerable amount of chlorine for its molecular structure. Flame-resistant polyethylene generates smoke much more than polyethylene without flame-resisting treatment because of its flame resistivity, but less than that of PVC. (Wakatsuki, Y.)

  17. Biochemical gas sensor (bio-sniffer) for ultrahigh-sensitive gaseous formaldehyde monitoring.

    Science.gov (United States)

    Kudo, Hiroyuki; Suzuki, Yuki; Gessei, Tomoko; Takahashi, Daishi; Arakawa, Takahiro; Mitsubayashi, Kohji

    2010-10-15

    An ultrahigh-sensitive fiber-optic biochemical gas sensor (bio-sniffer) for continuous monitoring of indoor formaldehyde was constructed and tested. The bio-sniffer measures gaseous formaldehyde as fluorescence of nicotinamide adenine dinucleotide (NADH), which is the product of formaldehyde dehydrogenase (FALDH) reaction. The bio-sniffer device was constructed by attaching a flow cell with a FALDH immobilized membrane onto a fiber-optic NADH measurement system. The NADH measurement system utilizes an ultraviolet-light emitting diode (UV-LED) with peak emission of 335 nm as an excitation light source. The excitation light was introduced to an optical fiber probe, and fluorescence emission of neighboring NADH, which was produced by applying formaldehyde vapor to the FALDH membrane, was concentrically measured with a photomultiplier tube. Assessment of the bio-sniffer was carried out using a standard gas generator. Response, calibration range and selectivity to other chemical substances were investigated. Circulating phosphate buffer, which contained NAD+, available for continuous monitoring of formaldehyde vapor. The calibration range of the bio-sniffer was 2.5 ppb to 10 ppm, which covers the guideline value of the World Health Organization (80 ppb). High selectivity to other gaseous substances due to specific activity of FALDH was also confirmed. Considering its high sensitivity, a possible application of the bio-sniffer is continuous indoor formaldehyde monitoring to provide healthy residential atmosphere. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. A radioactive noble gas quantitative analysis of gaseous effluents from NPP

    International Nuclear Information System (INIS)

    Yanev, Y.; Georgiev, K.; Mavrodiev, V.; Kikarin, B.

    1993-01-01

    The radioactive isotopes of argon, krypton and xenon comprise a substantial part of the gaseous emission of a NPP. A quantitative determination of their specific activity in the controlled area and the gaseous effluents requires a special sampling technique, as well as measurement method. The zeolites and the activated charcoals have a differentiated behaviour towards radioisotopes of argon, krypton and xenon. The isotope fractionation is often a problem, especially with argon and xenon. Some additional difficulties arise due to the irreproductibility of temperature and atmospheric moisture. The present paper describes a method for a spectrometric determination of radioactive noble gases after the cryogenic sampling developed at the Radiochemical laboratory of the Sofia University. The quality control of the method, as well as some special difficulties in its performing are discussed. The estimated minimum detectable activity is 5-10 Bq/m 3 for radioactive noble gases with half-life > 1 hour and sampling time for (resp. gamma-spectrometry) 1 hour. (author)

  19. Operational experience of gaseous effluent treatment at the Eurochemic reprocessing plant

    International Nuclear Information System (INIS)

    Osipenco, A.; Detilleux, E.

    1977-01-01

    The EUROCHEMIC fuel reprocessing plant applies the PUREX flow sheet. Two particular features of the plant influence gaseous and liquid effluents: chemical decanning and the ability to process a wide range of fuels, uranium metal or oxide, having an initial enrichment typical of power reactors (up to 5%) or material testing reactors (up to 93%). The ventilation circuits, treatment plant and monitoring equipment for gaseous releases are briefly described. No retention facilities for rare gases, tritium, or carbon-14 are provided. The releases are monitored for krypton-85, iodine-131, alpha and beta-gamma aerosols and tritium. Between 1966 and 1974 the plant processes about 200 tonnes of power reactor fuel, from which about 0.7 tonnes of plutonium and 1.5 tonnes of highly enriched uranium were separated. The most important points in the operation of the gas cleaning equipment are indicated: efficiency, operational reliability, incidents, etc.. Actual discharges as measured are compared with the limits set in the operation licence. Using the atmospheric diffusion coefficients, the dose commitment is estimated. The low level liquid effluents are passed, after neutralization, to the treatment plant of the Belgian nuclear center CEN/SCK. However, if the activity exceeds the limit set by the CEN/SCK, the effluents are concentrated by evaporation and stored on the EUROCHEMIC site. (orig.) [de

  20. Techniques to limit gaseous releases in case of reactor accident. Choice criteria - present solutions

    International Nuclear Information System (INIS)

    Billard, Francois; Lavie, Jean-Marie

    1964-10-01

    Within the frame of the study of radiological risks associated with a reactor accident in order to define the required responses, this study comprises, on the one hand, an analysis of the different accident types in order to select typical accidents, and on the other hand, a site-based analysis to define the maximum admissible radioactivity release for a given site. The determination of minimum required coefficient of risk reduction results from a compromise between the choice of reactor configuration type and the efficiency of purification devices, while taking into account minimum characteristics of the enclosure mechanical strength, local release conditions, and nature of gaseous effluents to be processed. After a review of available containment techniques, the author applies this analysis method to the different French reactor types. He gives a brief description of adopted solutions for the most typical French reactors in terms of characteristics of venting and filtration devices. As data quality is a crucial requirement, the author outlines the need for further studies regarding fission product emission and transfer, the purification of gaseous effluents and their diffusion in the atmosphere [fr

  1. Natural and anthropogenic atmospheric mercury in the European Arctic: a fractionation study

    OpenAIRE

    A. O. Steen; T. Berg; A. P. Dastoor; D. A. Durnford; O. Engelsen; L. R. Hole; K. A. Pfaffhuber

    2011-01-01

    Gaseous elemental mercury (GEM) is converted to reactive gaseous mercury (RGM) during springtime Atmospheric Mercury Depletion Events (AMDE).

    This study reports the longest time series of GEM, RGM and particle-bound mercury (PHg) concentrations from a European Arctic site. From 27 April 2007 until 31 December 2008 composite GEM, RGM and PHg measurements were conducted in Ny-Ålesund (78° 54′ N, 11° 53′ E). The average concentrations of t...

  2. Natural and anthropogenic atmospheric mercury in the European Arctic: a speciation study

    OpenAIRE

    Steen, Anne Orderdalen; Berg, Torunn; Dastoor, Ashu P.; Durnford, Dorothy, A.; Hole, Lars Robert; Pfaffhuber, Katrine Aspmo

    2010-01-01

    It is agreed that gaseous elemental mercury (GEM) is converted to reactive gaseous mercury (RGM) during springtime Atmospheric Mercury Depletion Event (AMDE). RGM is associated with aerosols (PHg) provided that there are sufficient aerosols available for the conversion from RGM to PHg to occur.

    This study reports the longest time series of GEM, RGM and PHg concentrations from a European Arctic site. From 27 April 2007 until 31 December 2008 composite GEM, RGM and PHg meas...

  3. Charge Transfer Properties Through Graphene for Applications in Gaseous Detectors

    CERN Document Server

    Franchino, S.; Hall-Wilton, R.; Jackman, R.B.; Muller, H.; Nguyen, T.T.; de Oliveira, R.; Oliveri, E.; Pfeiffer, D.; Resnati, F.; Ropelewski, L.; Smith, J.; van Stenis, M.; Streli, C.; Thuiner, P.; Veenhof, R.

    2016-07-11

    Graphene is a single layer of carbon atoms arranged in a honeycomb lattice with remarkable mechanical and electrical properties. Regarded as the thinnest and narrowest conductive mesh, it has drastically different transmission behaviours when bombarded with electrons and ions in vacuum. This property, if confirmed in gas, may be a definitive solution for the ion back-flow problem in gaseous detectors. In order to ascertain this aspect, graphene layers of dimensions of about 2x2cm$^2$, grown on a copper substrate, are transferred onto a flat metal surface with holes, so that the graphene layer is freely suspended. The graphene and the support are installed into a gaseous detector equipped with a triple Gaseous Electron Multiplier (GEM), and the transparency properties to electrons and ions are studied in gas as a function of the electric fields. The techniques to produce the graphene samples are described, and we report on preliminary tests of graphene-coated GEMs.

  4. Gaseous waste processing device in nuclear power plant

    International Nuclear Information System (INIS)

    Takechi, Eisuke; Matsutoshi, Makoto.

    1978-01-01

    Purpose: To arrange the units of waste processing devices in a number one more than the number thereof required for a plurality of reactors, and to make it usable commonly as a preliminary waste processing device thereby to effectively use all the gaseous waste processing devices. Constitution: A gaseous waste processing device is constituted by an exhaust gas extractor, a first processing device, a second processing device and the like, which are all connected in series. Upon this occasion, devices from the exhaust gas extractor to the first processing device and valves, which are provided in each of reactors, are arranged in series, on one hand, but valves at the downstream side join one another by one pipeline, and are connected to a stack through a total gaseous waste processing device, on another. (Yoshihara, H.)

  5. Gaseous detectors for energy dispersive X-ray fluorescence analysis

    Science.gov (United States)

    Veloso, J. F. C. A.; Silva, A. L. M.

    2018-01-01

    The energy resolution capability of gaseous detectors is being used in the last years to perform studies on the detection of characteristic X-ray lines emitted by elements when excited by external radiation sources. One of the most successful techniques is the Energy Dispersive X-ray Fluorescence (EDXRF) analysis. Recent developments in the new generation of micropatterned gaseous detectors (MPGDs), triggered the possibility not only of recording the photon energy, but also of providing position information, extending their application to EDXRF imaging. The relevant features and strategies to be applied in gaseous detectors in order to better fit the requirements for EDXRF imaging will be reviewed and discussed, and some application examples will be presented.

  6. Transmission environmental scanning electron microscope with scintillation gaseous detection device.

    Science.gov (United States)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-03-01

    A transmission environmental scanning electron microscope with use of a scintillation gaseous detection device has been implemented. This corresponds to a transmission scanning electron microscope but with addition of a gaseous environment acting both as environmental and detection medium. A commercial type of low vacuum machine has been employed together with appropriate modifications to the detection configuration. This involves controlled screening of various emitted signals in conjunction with a scintillation gaseous detection device already provided with the machine for regular surface imaging. Dark field and bright field imaging has been obtained along with other detection conditions. With a progressive series of modifications and tests, the theory and practice of a novel type of microscopy is briefly shown now ushering further significant improvements and developments in electron microscopy as a whole. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Extruder system and method for treatment of a gaseous medium

    Energy Technology Data Exchange (ETDEWEB)

    Silvi, Norberto; Perry, Robert James; Singh, Surinder Prabhjot; Balch, Gary Stephen; Westendorf, Tiffany Elizabeth Pinard

    2016-04-05

    A system for treatment of a gaseous medium, comprises an extruder having a barrel. The extruder further comprises a first inlet port, a second inlet port, and a plurality of outlet ports coupled to the barrel. The first inlet port is configured for feeding a lean sorbent, the second inlet port is configured for feeding a gaseous medium, and the plurality of outlet ports are configured for releasing a plurality of components removed from the gaseous medium. Further, the extruder comprises a plurality of helical elements coupled to a plurality of kneading elements, mounted on a shaft, and disposed within the barrel. The barrel and the plurality of helical and kneading elements together form an absorption unit and a desorption unit. The first and second inlet ports are formed in the absorption unit and the plurality of outlet ports are formed in the absorption and desorption units.

  8. Dispersion of UO2F2 aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.

    1996-01-01

    The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF 6 ) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF 6 is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H 2 O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO 2 F 2 ). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO 2 F 2 aerosols throughout the operating floor area following B-line break accident in the cell floor area

  9. Rare earths in iron and steelmaking and gaseous desulphurisation

    International Nuclear Information System (INIS)

    Kay, D.A.R.; Subramanian, S.V.; Meng, V.; Kumar, R.V.

    1985-01-01

    Rare earth (RE) additions, either as mischmetal or rare earth silicide, are used in many ladle treatment processes in modern ferrous metallurgy. In ironmaking they provide the basis for the control of graphite morphology in cast irons and in steelmaking additions are made to aluminum-killed steels for desulphurisation and the control of inclusion composition and morphology. Rare earth oxides may also be used in the desulphurisation of medium calorific value gaseous fuels and stack gases. In this paper, Ce-S-O and La-S-O phase stability diagrams are used to determine the role of the rare earths in the external processing of iron and steel, and gaseous desulphurisation

  10. 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

  11. Electron impact phenomena and the properties of gaseous ions

    CERN Document Server

    Field, F H; Massey, H S W; Brueckner, Keith A

    1970-01-01

    Electron Impact Phenomena and the Properties of Gaseous Ions, Revised Edition deals with data pertaining to electron impact and to molecular gaseous ionic phenomena. This book discusses electron impact phenomena in gases at low pressure that involve low-energy electrons, which result in ion formation. The text also describes the use of mass spectrometers in electron impact studies and the degree of accuracy obtained when measuring electron impact energies. This book also reviews relatively low speed electrons and the transitions that result in the ionization of the atomic system. This text the

  12. First Measurements of Ambient Total Gaseous Mercury (TGM at the EvK2CNR Pyramid Observatory in Nepal

    Directory of Open Access Journals (Sweden)

    Gratz L. E.

    2013-04-01

    Full Text Available As part of the Global Mercury Observation System (GMOS project, a global-scale network of ground-based atmospheric monitoring sites is being developed with the objective of expanding the global coverage of atmospheric mercury (Hg measurements and improving our understanding of global atmospheric Hg transport. An important addition to the GMOS monitorng network has been the high altitude EvK2CNR Pyramid Observatory, located at an elevation of 5,050 meters a.s.l. in the eastern Himalaya Mountains of Nepal. Monitoring of total gaseous mercury (TGM using the Tekran 2537A Mercury Vapor Analyzer began at the EvK2CNR Pyramid Observatory in November 2011. From 17 November 2011 to 23 April 2012, the mean concentration of TGM at the Pyramid was 1.2 ng m−3. A range of concentrations from 0.7 to 2.6 ng m−3 has been observed. These are the first reported measurements of atmospheric Hg in Nepal, and currently this is the highest altitude monitoring station for atmospheric Hg in the world. It is anticipated that these high quality measurements, in combination with the other continuous atmospheric measurments being collected at the Pyramid station, will help to further our understanding of Hg concentrations in the free troposphere and the transport of atmospheric Hg on the global scale.

  13. Atmospheric Electricity

    Science.gov (United States)

    Aplin, Karen; Fischer, Georg

    2018-02-01

    Electricity occurs in atmospheres across the Solar System planets and beyond, spanning spectacular lightning displays in clouds of water or dust, to more subtle effects of charge and electric fields. On Earth, lightning is likely to have existed for a long time, based on evidence from fossilized lightning strikes in ancient rocks, but observations of planetary lightning are necessarily much more recent. The generation and observations of lightning and other atmospheric electrical processes, both from within-atmosphere measurements, and spacecraft remote sensing, can be readily studied using a comparative planetology approach, with Earth as a model. All atmospheres contain charged molecules, electrons, and/or molecular clusters created by ionization from cosmic rays and other processes, which may affect an atmosphere's energy balance both through aerosol and cloud formation, and direct absorption of radiation. Several planets are anticipated to host a "global electric circuit" by analogy with the circuit occurring on Earth, where thunderstorms drive current of ions or electrons through weakly conductive parts of the atmosphere. This current flow may further modulate an atmosphere's radiative properties through cloud and aerosol effects. Lightning could potentially have implications for life through its effects on atmospheric chemistry and particle transport. It has been observed on many of the Solar System planets (Earth, Jupiter, Saturn, Uranus, and Neptune) and it may also be present on Venus and Mars. On Earth, Jupiter, and Saturn, lightning is thought to be generated in deep water and ice clouds, but discharges can be generated in dust, as for terrestrial volcanic lightning, and on Mars. Other, less well-understood mechanisms causing discharges in non-water clouds also seem likely. The discovery of thousands of exoplanets has recently led to a range of further exotic possibilities for atmospheric electricity, though lightning detection beyond our Solar System

  14. Femtosecond Time-Resolved Resonance-Enhanced CARS of Gaseous Iodine at Room Temperature

    International Nuclear Information System (INIS)

    He Ping; Fan Rong-Wei; Xia Yuan-Qin; Yu Xin; Chen De-Ying; Yao Yong

    2011-01-01

    Time-resolved resonance-enhanced coherent anti-Stokes Raman scattering (CARS) is applied to investigate molecular dynamics in gaseous iodine. 40 fs laser pulses are applied to create and monitor the high vibrational states of iodine at room temperature (corresponding to a vapor pressure as low as about 35 Pa) by femtosecond time-resolved CARS. Depending on the time delay between the probe pulse and the pump/Stokes pulse pairs, the high vibrational states both on the electronically ground states and the excited states can be detected as oscillations in the CARS transient signal. It is proved that the femtosecond time-resolved CARS technique is a promising candidate for investigating the molecular dynamics of a low concentration system and can be applied to environmental and atmospheric monitoring measurements. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Fate of gaseous tritium and carbon-14 released from buried low-level radioactive waste

    International Nuclear Information System (INIS)

    Striegl, R.G.

    1988-01-01

    Microbial decomposition, chemical degradation, and volatilization of buried low-level radioactive waste results in the release of gases containing tritium ( 3 H) and carbon-14 ( 14 C) to the surrounding environment. Water vapor, carbon dioxide, and methane that contain 3 H or 14 C are primary products of microbial decomposition of the waste. Depending on the composition of the waste source, chemical degradation and volatilization of waste also may result in the production of a variety of radioactive gases and organic vapors. Movement of the gases in materials that surround waste trenches is affected by physical, geochemical, and biological mechanisms including sorption, gas-water-mineral reactions, isotopic dilution, microbial consumption, and bioaccumulation. These mechanisms either may transfer 3 H and 14 C to solids and infiltrating water or may result in the accumulation of the radionuclides in plant or animal tissue. Gaseous 3 H or 14 C that is not transferred to other forms is ultimately released to the atmosphere

  16. Direct estimation of diffuse gaseous emissions from coal fires: current methods and future directions

    Science.gov (United States)

    Engle, Mark A.; Olea, Ricardo A.; O'Keefe, Jennifer M. K.; Hower, James C.; Geboy, Nicholas J.

    2013-01-01

    Coal fires occur in nature spontaneously, contribute to increases in greenhouse gases, and emit atmospheric toxicants. Increasing interest in quantifying coal fire emissions has resulted in the adaptation and development of specialized approaches and adoption of numerical modeling techniques. Overview of these methods for direct estimation of diffuse gas emissions from coal fires is presented in this paper. Here we take advantage of stochastic Gaussian simulation to interpolate CO2 fluxes measured using a dynamic closed chamber at the Ruth Mullins coal fire in Perry County, Kentucky. This approach allows for preparing a map of diffuse gas emissions, one of the two primary ways that gases emanate from coal fires, and establishing the reliability of the study both locally and for the entire fire. Future research directions include continuous and automated sampling to improve quantification of gaseous coal fire emissions.

  17. Conversion factors for estimating release rate of gaseous radioactivity by an aerial survey

    International Nuclear Information System (INIS)

    Saito, Kimiaki; Moriuchi, Shigeru

    1988-02-01

    Conversion factors necessary for estimating release rate of gaseous radioactivity by an aerial survey are presented. The conversion factors were determined based on calculation assuming a Gaussian plume model as a function of atmospheric stability, down-wind distance and flight height. First, the conversion factors for plumes emitting mono-energy gamma rays were calculated, then, conversion factors were constructed through convolution for the radionuclides essential in an accident of a nuclear reactor, and for mixtures of these radionuclides considering elapsed time after shutdown. These conversion factors are shown in figures, and also polynomial expressions of the conversion factors as a function of height have been decided with the least-squares method. A user can easily obtain proper conversion factors from data shown here. (author)

  18. Microscale diffusion analysis of gaseous radioactive effluents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byung Woo; Chang, Kwang Phil; Jeong, Guy Soo; Lee, Kwang Hee; Choi, Yong Seok; An, Jin Young [Sungkyunkwan University, Seoul (Korea, Republic of)

    1997-07-01

    The state-of-the art review and relevant data bases have been made in this study. Microscale wind-field model has been made and applied to the site= of a target domestic plant - Younggwang units. Following researches have been made; - Review of modeling status in U.S.A., European countries, and Japan, those theoretical backgrounds, and experimental activities - Graphical display of topographical grid data in the surrounding with the Younggwang N.P.P. and basic investigation of the surrounding geography - Survey of site meteorological data of the Younggwang N.P.P.; precipitation distribution, yearly average wind direction and joint frequency, seasonal wind rose, distribution of seasonal sea and land breeze, joint frequency with respect to the atmospheric stability, mixing height - Presentation of a draft to update the existing Korea real-time dose assessment system, FADAS and to interface to the AWS(Automatic Weather System) of the Korea Meteorology Administration. - Establishment of nested-grid system with micro- and macro- scale cells around the Younggwang nuclear power plant -Consideration of solar radiation effect by using land-use map -Analysis of wind field in the region of 30 x 30 km n the Younggwang site (Author) 67 refs., 20 tabs., 28 figs.

  19. Scavenging of gaseous mercury by acidic snow at Kuujjuarapik, Northern Quebec

    International Nuclear Information System (INIS)

    Lahoutifard, Nazafarin; Poissant, Laurier; Scott, Susannah L.

    2006-01-01

    One fate of gaseous elemental mercury (GEM) in the Arctic has been identified as gas phase oxidation by halogen-containing radicals, leading to abrupt atmospheric mercury depletion concurrent with ozone depletion. Rapid deposition of oxidized mercury leads to snow enrichment in mercury. In this report, we describe experiments that demonstrate the ability of snow to directly scavenge atmospheric mercury. The study was conducted at Kuujjuarapik, Quebec, Canada (latitude 55 o 17'N). A mercury depletion event (MDE) caused the mercury concentration in the surface snow of the coastal snowpack to double, from (9.4 ± 2.0) to (19.2 ± 1.7) ng/L. Independent of the MDE, mercury concentrations increased five-fold, from (10.0 ± 0.1) to (51.4 ± 6.0) ng/L, upon spiking the snow with 500 μM hydrogen peroxide under solar irradiation. Total organic carbon in the spiked irradiated snow samples also decreased, consistent with the formation of strongly oxidizing species. The role of the snowpack in releasing GEM to the atmosphere has been reported; these findings suggest that snow may also play a role in enhancing deposition of mercury

  20. Monitoring of gaseous elemental mercury in central Antarctica at Dome Concordia

    Directory of Open Access Journals (Sweden)

    Dommergue A.

    2013-04-01

    Full Text Available Within the framework of the Global Mercury Observation System (GMOS, we are monitoring gaseous elemental mercury (Hg(0 at the Dome Concordia Station to improve our understanding of atmospheric Hg in the Antarctic atmosphere. This French-Italian facility is located in one of the coldest places on the planet and is situated on the vast Antarctic Plateau at an elevation of 3320 m. Continuous measurements began on December 7, 2011 and are ongoing. The median value calculated over the period (n=24506 is approximately 0.9 ng/m3 and values range from <0.1 ng/m3 up to 2.3 ng/m3. Preliminary results suggest that the Antarctic atmospheric boundary layer is a very reactive place during the periods when sunlight is present. A combination of fast and efficient oxidation processes with snow photochemistry lead to a dynamic record of Hg(0 unlike any other location. Our improved understanding of these processes will help to better constrain the cycle of Hg in the Southern Hemisphere.

  1. Mars: Atmosphere

    Science.gov (United States)

    Moroz, V.; Murdin, P.

    2001-07-01

    The atmosphere of MARS is much thinner than the terrestrial one. However, even the simplest visual telescopic observations show a set of atmospheric events such as seasonal exchange of material between polar caps, temporal appearance of clouds and changes of visibility of dark regions on the disk of the planet. In 1947 the prominent CO2 bands in the near-infrared part of the Martian spectrum were...

  2. EXAMINING TATOOINE: ATMOSPHERIC MODELS OF NEPTUNE-LIKE CIRCUMBINARY PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    May, E. M.; Rauscher, E. [University of Michigan (United States)

    2016-08-01

    Circumbinary planets experience a time-varying irradiation pattern as they orbit their two host stars. In this work, we present the first detailed study of the atmospheric effects of this irradiation pattern on known and hypothetical gaseous circumbinary planets. Using both a one-dimensional energy balance model (EBM) and a three-dimensional general circulation model (GCM), we look at the temperature differences between circumbinary planets and their equivalent single-star cases in order to determine the nature of the atmospheres of these planets. We find that for circumbinary planets on stable orbits around their host stars, temperature differences are on average no more than 1.0% in the most extreme cases. Based on detailed modeling with the GCM, we find that these temperature differences are not large enough to excite circulation differences between the two cases. We conclude that gaseous circumbinary planets can be treated as their equivalent single-star case in future atmospheric modeling efforts.

  3. Gaseous elemental mercury (GEM) fluxes over canopy of two typical subtropical forests in south China

    Science.gov (United States)

    Yu, Qian; Luo, Yao; Wang, Shuxiao; Wang, Zhiqi; Hao, Jiming; Duan, Lei

    2018-01-01

    Mercury (Hg) exchange between forests and the atmosphere plays an important role in global Hg cycling. The present estimate of global emission of Hg from natural source has large uncertainty, partly due to the lack of chronical and valid field data, particularly for terrestrial surfaces in China, the most important contributor to global atmospheric Hg. In this study, the micrometeorological method (MM) was used to continuously observe gaseous elemental mercury (GEM) fluxes over forest canopy at a mildly polluted site (Qianyanzhou, QYZ) and a moderately polluted site (Huitong, HT, near a large Hg mine) in subtropical south China for a full year from January to December in 2014. The GEM flux measurements over forest canopy in QYZ and HT showed net emission with annual average values of 6.67 and 0.30 ng m-2 h-1, respectively. Daily variations of GEM fluxes showed an increasing emission with the increasing air temperature and solar radiation in the daytime to a peak at 13:00, and decreasing emission thereafter, even as a GEM sink or balance at night. High temperature and low air Hg concentration resulted in the high Hg emission in summer. Low temperature in winter and Hg absorption by plant in spring resulted in low Hg emission, or even adsorption in the two seasons. GEM fluxes were positively correlated with air temperature, soil temperature, wind speed, and solar radiation, while it is negatively correlated with air humidity and atmospheric GEM concentration. The lower emission fluxes of GEM at the moderately polluted site (HT) when compared with that in the mildly polluted site (QYZ) may result from a much higher adsorption fluxes at night in spite of a similar or higher emission fluxes during daytime. This shows that the higher atmospheric GEM concentration at HT restricted the forest GEM emission. Great attention should be paid to forests as a crucial increasing Hg emission source with the decreasing atmospheric GEM concentration in polluted areas because of Hg

  4. Radioactive gaseous waste management activities at CWMF

    International Nuclear Information System (INIS)

    Sumangala, R.K; Cheralathan, M.; Hariharan, P.T.; Chitra, S.; Paul, B.

    2015-01-01

    HEPA and iodine filter banks are used as an important engineering safeguard to prevent the release of airborne activity to the environment during normal and accident conditions in all nuclear installations. CWMF is responsible for the periodical testing and certification these filter banks as per the technical specification of the nuclear facilities at Kalpakkam site. An efficiency of >99.9% is ensured for both the HEPA as well as iodine filter banks. The larger radioactive particulates are trapped in the micro glass fibre filter paper medium by the mechanism of interception and inertial impaction whereas particulates of submicron size are caught by diffusion. The major activity removed in particulate form is 137 Cs and 90 Sr. The elemental iodine is removed by physico-chemical adsorption on high surface area activated charcoal and organic compounds of iodine are removed by isotopic exchange with KI/KOH impregnated activated charcoal or silver impregnated silica gel. Silver impregnated molecular sieves 13-X and AR-1 were developed for the removal of iodine from reprocessing atmosphere. Studies on pressure swing adsorption technique have been carried out for isolating Argon from air. Using Molecular sieve 5A (45psi-50psi) and Carbon molecular sieves (100psi to 120psi) based PSA systems in series an enrichment of 30% Ar is possible. Pressurized Heavy Water Reactors with calandria vault coolant as air produces 41 Ar due to neutron activation of 40 Ar present in air which main contributor to the air is borne activity in MAPS, RAPS and Dhruva reactors. The isolated argon can be stored for decay and activity release can be minimized as per ALARA principle. (author)

  5. Neutron and thermal dynamics of a gaseous core fission reactor

    International Nuclear Information System (INIS)

    van Dam, H.; Kuijper, J.C.; Stekelenburg, A.J.C.; Hoogenboom, J.E.; Boersma-Klein, W.; Kistemaker, J.

    1989-01-01

    In this paper neutron kinetics and thermal dynamics of a Gaseous Core Fission Reactor with magnetical pumping are shown to have many unconventional aspects. Attention is focused on the properties of the fuel gas, the non-linear neutron kinetics and the energy balance in thermodynamical cycles

  6. Reactor physics and thermodynamics of a gaseous core fission reactor

    International Nuclear Information System (INIS)

    Kuijper, J.C.; Van Dam, H.; Stekelenburg, A.J.C.; Hoogenboom, J.E.; Boersma-Klein, W.; Kistemaker, J.

    1990-01-01

    Neutron kinetics and thermodynamics of a Gaseous Core Fission Reactor with magnetical pumping are shown to have many unconventional aspects. Attention is focussed on the properties of the fuel gas, the stationary temperature distribution, the non-linear neutron kinetics and the energy balance in thermodynamical cycles

  7. Transmission environmental scanning electron microscope with scintillation gaseous detection device

    International Nuclear Information System (INIS)

    Danilatos, Gerasimos; Kollia, Mary; Dracopoulos, Vassileios

    2015-01-01

    A transmission environmental scanning electron microscope with use of a scintillation gaseous detection device has been implemented. This corresponds to a transmission scanning electron microscope but with addition of a gaseous environment acting both as environmental and detection medium. A commercial type of low vacuum machine has been employed together with appropriate modifications to the detection configuration. This involves controlled screening of various emitted signals in conjunction with a scintillation gaseous detection device already provided with the machine for regular surface imaging. Dark field and bright field imaging has been obtained along with other detection conditions. With a progressive series of modifications and tests, the theory and practice of a novel type of microscopy is briefly shown now ushering further significant improvements and developments in electron microscopy as a whole. - Highlights: • Novel scanning transmission electron microscopy (STEM) with an environmental scanning electron microscope (ESEM) called TESEM. • Use of the gaseous detection device (GDD) in scintillation mode that allows high resolution bright and dark field imaging in the TESEM. • Novel approach towards a unification of both vacuum and environmental conditions in both bulk/surface and transmission mode of electron microscopy

  8. Absorption of continuum radiation in a resonant expanding gaseous sphere

    International Nuclear Information System (INIS)

    Shaparev, N Y

    2014-01-01

    The paper deals with absorption of external continuum radiation in a self-similarly expanding gaseous sphere. Frequency probability and integral probability of radiation absorption in the resonance frequency range are determined depending on the expansion velocity gradient and thickness of the optical medium. It is shown that expansion results in a reduced optical thickness of the medium and enhanced integral absorption. (paper)

  9. Separation of gaseous air pollutants using membrane contactors

    Science.gov (United States)

    Sverak, T.; Bulejko, P.; Ostrezi, J.; Kristof, O.; Kalivoda, J.; Kejik, P.; Mayerova, K.; Adamcik, M.

    2017-10-01

    This work deals with the separation of CO2 gaseous pollutant from gas mixtures to a water solution using the laboratory contactor. The laboratory set process parameters showed the rate of carbon dioxide transition through the interface in a so promising level the contactor separators can be considered as a very promising pathway to reduce the content of this greenhouse gas from the air.

  10. Engineering design of the Aries-IV gaseous divertor

    International Nuclear Information System (INIS)

    Hasan, M.Z.; Najmabadi, F.; Sharafat, S.

    1994-01-01

    ARIES-IV is a conceptual, D-T burning, steady-state tokamak fusion reactor producing 1000 MWe net. It operates in the second plasma stability regime. The structural material is SiC composite and the primary coolant is helium at 10MPa base pressure. ARIES-IV uses double-null divertors for particle control. Total thermal power recovered from the divertors is 425MW, which is 16% of the total reactor thermal power. Among the desirable goals of divertor design were to avoid the use of tungsten and to use the same structural material and primary coolant as in the blanket design. In order to reduce peak heat flux, the innovative gaseous divertor has been used in ARIES-IV. A gaseous divertor reduces peak heat flux by increasing the surface area and by distributing particle and radiation energy more uniformly. Another benefit of gaseous divertor is the reduction of plasma temperature in the divertor chamber, so that material erosion due to sputtering, can be diminished. This makes the use of low-Z material possible in a gaseous divertor

  11. Fabrication of HTR fuel elements by a gaseous impregnation process

    International Nuclear Information System (INIS)

    Blin, J.C.; Berthier, J.; Devillard, J.

    1976-01-01

    The results obtained with the gaseous impregnation process are described. The successive steps of the fabrication in their present state of realization are given together with the results obtained after irradiation. A comparison between this process and a classical method is presented

  12. Radioactive effluents, Portsmouth Gaseous Diffusion Plant, calendar year 1982

    International Nuclear Information System (INIS)

    Acox, T.A.; Hary, L.F.; Klein, L.S.

    1983-03-01

    Radioactive discharges from the Portsmouth Gaseous Diffusion Plant are discussed and tabulated. Tables indicate both the location of the discharge and the nuclides discharged. All discharges for 1982 are well below the Radioactive Concentration Guide limits specified in DOE Order 5480.1, Chapter XI. 1 figure

  13. Microstructural and compositional Evolution of Compound Layers during Gaseous Nitrocarburizing

    DEFF Research Database (Denmark)

    Du, Hong; Somers, Marcel A.J.; Ågren, John

    2000-01-01

    Compound layers developed at 848 K during gaseous nitrocarburizing of iron and iron-carbon specimens were investigated for several combinations of N and C activities imposed at the specimen surface by gas mixtures of NH3, N2, CO2 and CO. The microstructural evolution of the compound layer was stu...

  14. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters. (LK)

  15. Transference system of gaseous fluoride compounds for infrared spectrofotometric analysis

    International Nuclear Information System (INIS)

    Prado, L.

    1988-07-01

    A vacuum line design for transference of gaseous fluoride compounds involved in the uranium hexafluoride infrared analysis is presented. The text include specific comments about the characteristics of each component and about the possibilities of its acquisition in the national market. (author) [pt

  16. Deuterium exchange between liquid water and gaseous hydrogen

    International Nuclear Information System (INIS)

    Dave, S.M.; Ghosh, S.K.; Sadhukhan, H.K.

    1982-01-01

    The overall separation factors for the deuterium exchange between liquid water and gaseous hydrogen have been calculated over a wide range of temperature, pressure and deuterium concentrations. These data would be useful in the design and other considerations for heavy water production, based on hydrogen-water exchange. (author)

  17. Inhalation gases or gaseous mediators as neuroprotectants for cerebral ischaemia.

    Science.gov (United States)

    Sutherland, Brad A; Harrison, Joanne C; Nair, Shiva M; Sammut, Ivan A

    2013-01-01

    Ischaemic stroke is one of the leading causes of morbidity and mortality worldwide. While recombinant tissue plasminogen activator can be administered to produce thrombolysis and restore blood flow to the ischaemic brain, therapeutic benefit is only achieved in a fraction of the subset of patients eligible for fibrinolytic intervention. Neuroprotective therapies attempting to restrict the extent of brain injury following cerebral ischaemia have not been successfully translated into the clinic despite overwhelming pre-clinical evidence of neuroprotection. Therefore, an adequate treatment for the majority of acute ischaemic stroke patients remains elusive. In the stroke literature, the use of therapeutic gases has received relatively little attention. Gases such as hyperbaric and normobaric oxygen, xenon, hydrogen, helium and argon all possess biological effects that have shown to be neuroprotective in pre-clinical models of ischaemic stroke. There are significant advantages to using gases including their relative abundance, low cost and feasibility for administration, all of which make them ideal candidates for a translational therapy for stroke. In addition, modulating cellular gaseous mediators including nitric oxide, carbon monoxide, and hydrogen sulphide may be an attractive option for ischaemic stroke therapy. Inhalation of these gaseous mediators can also produce neuroprotection, but this strategy remains to be confirmed as a viable therapy for ischaemic stroke. This review highlights the neuroprotective potential of therapeutic gas therapy and modulation of gaseous mediators for ischaemic stroke. The therapeutic advantages of gaseous therapy offer new promising directions in breaking the translational barrier for ischaemic stroke.

  18. Methods for deacidizing gaseous mixtures by phase enhanced absorption

    Science.gov (United States)

    Hu, Liang

    2012-11-27

    An improved process for deacidizing a gaseous mixture using phase enhanced gas-liquid absorption is described. The process utilizes a multiphasic absorbent that absorbs an acid gas at increased rate and leads to reduced overall energy costs for the deacidizing operation.

  19. Nuclear waste disposal utilizing a gaseous core reactor

    Science.gov (United States)

    Paternoster, R. R.

    1975-01-01

    The feasibility of a gaseous core nuclear reactor designed to produce power to also reduce the national inventories of long-lived reactor waste products through nuclear transmutation was examined. Neutron-induced transmutation of radioactive wastes is shown to be an effective means of shortening the apparent half life.

  20. gaseous emissions from some industries at ama industrial complex ...

    African Journals Online (AJOL)

    user

    2015-08-11

    Aug 11, 2015 ... air quality standards. Therefore, it is recommended that these companies should determine appropriate control measures to reduce these toxic emissions. Key words: Toxic gaseous emissions, type, concentrations, Ama Industrial Complex, Nigeria. INTRODUCTION. Air pollutants such as carbon dioxide ...

  1. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanite “layers” on stainless steel are addressed....

  2. Plant air systems safety study: Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    1982-05-01

    The Portsmouth Gaseous Diffusion Plant Air System facilities and operations are reviewed for potential safety problems not covered by standard industrial safety procedures. Information is presented under the following section headings: facility and process description (general); air plant equipment; air distribution system; safety systems; accident analysis; plant air system safety overview; and conclusion

  3. Determination of some toxic gaseous emissions at Ama Industrial ...

    African Journals Online (AJOL)

    Determination of some toxic gaseous emissions at Ama Industrial Complex, Enugu, south eastern Nigeria. ... PROMOTING ACCESS TO AFRICAN RESEARCH ... A study of some gases emitted from three industries at Ama industrial complex, Nigeria, was carried out ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  4. Charge amplitude distribution of the Gossip gaseous pixel detector

    NARCIS (Netherlands)

    Blanco Carballo, V.M.; Chefdeville, M.A.; Colas, P.; Giomataris, Y.; van der Graaf, H.; Gromov, V.; Hartjes, F.; Kluit, R.; Koffeman, E.; Salm, Cora; Schmitz, Jurriaan; Smits, Sander M.; Timmermans, J.; Timmermans, J.; Visschers, J.L.

    2007-01-01

    The Gossip gaseous pixel detector is being developed for the detection of charged particles in extreme high radiation environments as foreseen close to the interaction point of the proposed super LHC. The detecting medium is a thin layer of gas. Because of the low density of this medium, only a few

  5. An introduction to technetium in the gaseous diffusion cascades

    International Nuclear Information System (INIS)

    Simmons, D.W.

    1996-09-01

    The radioisotope technetium-99 ( 99 Tc) was introduced into the gaseous diffusion plants (GDP) as a contaminant in uranium that had been reprocessed from spent nuclear reactor fuel. 99 Tc is a product of the nuclear fission of uranium-235 ( 235 U). The significantly higher emitted radioactivity of 99 Tc generates concern in the enrichment complex and warrants increased attention (1) to the control of all site emissions, (2) to worker exposures and contamination control when process equipment requires disassembly and decontamination, and (3) to product purity when the enriched uranium hexafluoride (UF 6 ) product is marketed to the private sector. A total of 101,268 metric tons of RU (∼96% of the total) was fed at the Paducah Gaseous Diffusion Plant (PGDP) between FY1953 and FY1976. An additional 5600 metric tons of RU from the government reactors were fed at the Oak Ridge Gaseous Diffusion Plant (ORGDP), plus an approximate 500 tons of foreign reactor returns. Only a small amount of RU was fed directly at the Portsmouth Gaseous Diffusion Plant (PORTS). The slightly enriched PGDP product was then fed to either the ORGDP or PORTS cascades for final enrichment. Bailey estimated in 1988 that of the 606 kg of Tc received at PGDP from RU, 121 kg was subsequently re-fed to ORGDP and 85 kg re-fed to PORTS

  6. Separation of tritium from gaseous and aqueous effluent systems

    International Nuclear Information System (INIS)

    Kobisk, E.H.

    1977-01-01

    Three processes are discussed for separating tritium from gaseous and aqueous effluent systems: separation in the gas phase using Pd-25 wt percent Ag alloy diffusion membranes; electrolytic separation in the aqueous phase using ''bipolar'' electrodes; and the countercurrent exchange of tritium-containing hydrogen gas with water on catalytic surfaces combined with separation by direct electrolysis

  7. Infrared scintillation: a comparison between gaseous and liquid xenon

    International Nuclear Information System (INIS)

    Bressi, G.; Carugno, G.; Conti, E.; Del Noce, C.; Iannuzzi, D.

    2001-01-01

    Light yield and spectrum of infrared (IR) scintillation in Xe are different in gaseous and liquid phases. In gas, the spectrum consists mainly of a broad line centered at 1300 nm. In liquid, light is emitted primarily below 1200 nm and with a lower yield

  8. The feasibility of the liberalization of the russian gaseous industry

    International Nuclear Information System (INIS)

    Locatelli, C.

    2002-11-01

    This paper deals with the main lines of the russian gaseous industry reform, Gazprom. The historical aspect and the objectives are discussed. After this presentation the author analyzes the uncertainties of the reform implementing, the constraints and the liberalization feasibility. (A.L.B.)

  9. Thermodynamic and transport properties of gaseous tetrafluoromethane in chemical equilibrium

    Science.gov (United States)

    Hunt, J. L.; Boney, L. R.

    1973-01-01

    Equations and in computer code are presented for the thermodynamic and transport properties of gaseous, undissociated tetrafluoromethane (CF4) in chemical equilibrium. The computer code calculates the thermodynamic and transport properties of CF4 when given any two of five thermodynamic variables (entropy, temperature, volume, pressure, and enthalpy). Equilibrium thermodynamic and transport property data are tabulated and pressure-enthalpy diagrams are presented.

  10. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

    International Nuclear Information System (INIS)

    1977-09-01

    Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters

  11. Characteristics and applications of small, portable gaseous air pollution monitors.

    Science.gov (United States)

    McKercher, Grant R; Salmond, Jennifer A; Vanos, Jennifer K

    2017-04-01

    Traditional approaches for measuring air quality based on fixed measurements are inadequate for personal exposure monitoring. To combat this issue, the use of small, portable gas-sensing air pollution monitoring technologies is increasing, with researchers and individuals employing portable and mobile methods to obtain more spatially and temporally representative air pollution data. However, many commercially available options are built for various applications and based on different technologies, assumptions, and limitations. A review of the monitor characteristics of small, gaseous monitors is missing from current scientific literature. A state-of-the-art review of small, portable monitors that measure ambient gaseous outdoor pollutants was developed to address broad trends during the last 5-10 years, and to help future experimenters interested in studying gaseous air pollutants choose monitors appropriate for their application and sampling needs. Trends in small, portable gaseous air pollution monitor uses and technologies were first identified and discussed in a review of literature. Next, searches of online databases were performed for articles containing specific information related to performance, characteristics, and use of such monitors that measure one or more of three criteria gaseous air pollutants: ozone, nitrogen dioxide, and carbon monoxide. All data were summarized into reference tables for comparison between applications, physical features, sensing capabilities, and costs of the devices. Recent portable monitoring trends are strongly related to associated applications and audiences. Fundamental research requires monitors with the best individual performance, and thus the highest cost technology. Monitor networking favors real-time capabilities and moderate cost for greater reproduction. Citizen science and crowdsourcing applications allow for lower-cost components; however important strengths and limitations for each application must be addressed

  12. Continuous determination of gaseous ammonia in the ambient atmosphere using fluorescence derivatization

    Science.gov (United States)

    Abbas, Rana; Tanner, Roger L.

    A method for continuous determination of ambient ammonia levels employing o-phthalaldehyde fluorescence derivatization is described. A simplified Venturi scrubber and gas-liquid separator have been employed for reproducible measurements of ⩾ 0.1 ppb ambient ammonia with less than 2 min time resolution. The scrubbing efficiency of the ammonia gas collection system was determined to be 29 ± 1 %. During 4 d in August 1979 ambient ammonia levels at the Brookhaven National Laboratory site averaged about 1.5 ± 1.1 ppb during afternoon daylight hours.

  13. Modelling land atmosphere exchange of gaseous oxides of nitrogen in Europe

    NARCIS (Netherlands)

    Duyzer, J.; Fowler, D.

    1994-01-01

    This review outlines current understanding of the exchange processes and methods used to estimate regional NOy deposition. Several methods have been used to measure dry deposition. Measurement artefacts such as non-stationarity caused by local sources, monitors responding to other gases than NO2 and

  14. Protection of atmospheric air against radioactive gas and aerosol contaminants

    International Nuclear Information System (INIS)

    Zykova, A.S.

    1984-01-01

    Measures for contamination protection of atmospheric air subdivided into active and passive ones, are considered. The active measures envisage: development and application of waste-free flowsheets, use of flowsheets which restrict formation of gaseous-aerosol discharges; application of highly efficient treatment facilities torage. Dispersion of radioactive substances, released with discharges to the atmosphere, using high stacks; development of the corresponding site-selection solutions and arrangement of sanitary protective zones belong to passive measures. Measures for protection of atmospheric air also include waste and air contamination monitoring. The measures described are considered as applied to NPPs

  15. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  16. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  17. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 2. Appendices

    International Nuclear Information System (INIS)

    1977-09-01

    Volume 2 is comprised of appendices: Portsmouth Gaseous Diffusion Plant Existing Facilities; Ecology; Civic Involvement; Social Analysis; Population Projections; Toxicity of Air Pollutants to Biota at Portsmouth Gaseous Diffusion Plant; and Assessment of Noise Effects of an Add-On to the Portsmouth Gaseous Diffusion Plant

  18. Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 2. Appendices. [Appendices only

    Energy Technology Data Exchange (ETDEWEB)

    Liverman, James L.

    1977-09-01

    Volume 2 is comprised of appendices: Portsmouth Gaseous Diffusion Plant Existing Facilities; Ecology; Civic Involvement; Social Analysis; Population Projections; Toxicity of Air Pollutants to Biota at Portsmouth Gaseous Diffusion Plant; and Assessment of Noise Effects of an Add-On to the Portsmouth Gaseous Diffusion Plant. (LK)

  19. Radioactivity in gaseous waste discharged from the separations facilities during 1978

    International Nuclear Information System (INIS)

    Anderson, J.D.; Poremba, B.E.

    1979-01-01

    This document is issued quarterly for the purpose of summarizing the radioactive gaseous wastes that are discharged from the facilities of the Rockwell Hanford Operations. Data on alpha and beta emissions during 1978 are presented where relevant to the gaseous effluent. Emission data are not included on gaseous wastes produced within the 200 Areas by other Hanford contractors

  20. Alarming atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2014-01-01

    Nurses working in the Neuro-Intensive Care Unit at Aarhus University Hospital lack the tools to prepare children for the alarming atmosphere they will enter when visiting a hospitalised relative. The complex soundscape dominated by alarms and sounds from equipment is mentioned as the main stressor...

  1. Seasonal trends in vegetation and atmospheric concentrations of PAHs and PBDEs near a sanitary landfill

    Science.gov (United States)

    St-Amand, Annick D.; Mayer, Paul M.; Blais, Jules M.

    Spruce needle and atmospheric (gaseous and particulate-bound) concentrations were surveyed near a sanitary landfill from February 2004 to June 2005. The influence of several parameters such as temperature, relative humidity, wind speed and direction, as well as increased domestic heating during the winter was assessed. In general, polybrominated diphenyl ethers (PBDE) and polycyclic aromatic hydrocarbons (PAH) concentrations in spruce needles increased over time and decreased following snowmelt with a minimum coinciding with bud burst of deciduous trees. Atmospheric concentrations of PBDE and PAH, both particulate-bound and gaseous phase, were linked to daily weather events and thus showed more variability than those in spruce needles. Highest PAH concentrations were encountered during the winter, likely reflecting increased emission from heating homes. Pseudo Clausius-Clapeyron plots revealed higher PBDE gaseous concentrations with increasing temperature, but showed no correlation between PAH gaseous concentrations and temperature as this effect was obscured by seasonal emission patterns. Finally, air mass back trajectories and local wind directions revealed that particulate-bound PBDEs, along with both gaseous and particulate-bound PAHs were from local sources, whereas gaseous PBDEs were likely from distant sources.

  2. Model, parameter and code of environmental dispersion of gaseous effluent under normal operation from nuclear power plant with 600 MWe

    International Nuclear Information System (INIS)

    Hu Erbang; Gao Zhanrong

    1998-06-01

    The model of environmental dispersion of gaseous effluence under normal operation from a nuclear power plant with 600 MWe is established to give a mathematical expression of annual mean atmospheric dispersion factor under mixing release condition based on quality assessment of radiological environment for 30 years of Chinese nuclear industry. In calculation, the impact from calm and other following factors have been taken into account: mixing layer, dry and wet deposition, radioactive decay and buildings. The doses caused from the following exposure pathways are also given by this model: external exposure from immersion cloud and ground deposition, internal exposure due to inhalation and ingestion. The code is named as ROULEA. It contains four modules, i.e. INPUT, ANRTRI, CHIQV and DOSE for calculating 4-dimension joint frequency, annual mean atmospheric dispersion factor and doses

  3. Paducah Gaseous Diffusion Plant Environmental report for 1990

    Energy Technology Data Exchange (ETDEWEB)

    Counce-Brown, D. (ed.)

    1991-09-01

    This two-part report, Paducah Gaseous Diffusion Plant Site Environmental Report for 1990, is published annually. It reflects the results of a comprehensive, year-round program to monitor the impact of operations at Paducah Gaseous Diffusion Plant (PGDP) on the area's groundwater and surface waters, soil, air quality, vegetation, and wildlife. In addition, an assessment of the effect of PGDP effluents on the resident human population is made. PGDP's overall goal for environmental management is to protect the environment and PGDP's neighbors and to maintain full compliance with all current regulations. The current environmental strategy is to identify any deficiencies and to develop a system to resolve them. The long-range goal of environmental management is to minimize the source of pollutants, to reduce the formation of waste, and to minimize hazardous waste by substitution of materials.

  4. Paducah Gaseous Diffusion Plant environmental report for 1992

    Energy Technology Data Exchange (ETDEWEB)

    Horak, C.M. [ed.] [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1993-09-01

    This two-part report, Paducah Gaseous Diffusion Plant Environmental Report for 1992, is published annually. It reflects the results of an environmental monitoring program designed to quantify potential increases in the concentration of contaminants and potential doses to the resident human population. The Paducah Gaseous Diffusion Plant (PGDP) overall goal for environmental management is to protect the environment and PGDP`s neighbors and to maintain full compliance with all current regulations. The current environmental strategy is to identify any deficiencies and to develop a system to resolve them. The long-range goal of environmental management is to minimize the source of pollutants, reduce the generation of waste, and minimize hazardous waste by substitution of materials.

  5. Distribution of xenon between gaseous and liquid CO2

    International Nuclear Information System (INIS)

    Ackley, R.D.; Notz, K.J.

    1976-10-01

    The distribution of xenon at low concentrations between gaseous and liquid CO 2 was measured over essentially the entire liquid range of CO 2 . These measurements involved using a collimated radiation-detection cell to determine the relative quantities of 133 Xe-traced xenon in the separate phases contained in a vertical cylinder under isothermal conditions. The results are expressed in terms of a distribution ratio (mole fraction of xenon in the gaseous phase divided by mole fraction of xenon in the liquid phase) which decreased from 7.53 at -54.8 0 C to 1.10 at 30.5 0 C. These data were used to calculate various other solubility-related quantities

  6. Paducah Gaseous Diffusion Plant environmental report for 1992

    International Nuclear Information System (INIS)

    Horak, C.M.

    1993-09-01

    This two-part report, Paducah Gaseous Diffusion Plant Environmental Report for 1992, is published annually. It reflects the results of an environmental monitoring program designed to quantify potential increases in the concentration of contaminants and potential doses to the resident human population. The Paducah Gaseous Diffusion Plant (PGDP) overall goal for environmental management is to protect the environment and PGDP's neighbors and to maintain full compliance with all current regulations. The current environmental strategy is to identify any deficiencies and to develop a system to resolve them. The long-range goal of environmental management is to minimize the source of pollutants, reduce the generation of waste, and minimize hazardous waste by substitution of materials

  7. Paducah Gaseous Diffusion Plant Annual Site Environmental Report for 1993

    International Nuclear Information System (INIS)

    1994-10-01

    The purpose of this document is to summarize effluent monitoring and environmental surveillance results and compliance with environmental laws, regulations, and orders at the Paducah Gaseous Diffusion Plant (PGDP). Environmental monitoring at PGDP consists of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring is direct measurement or the collection and analysis of samples of liquid and gaseous discharges to the environment. Environmental surveillance is direct measurement or the collection and analysis of samples of air, water, soil, foodstuff, biota, and other media. Environmental monitoring is performed to characterize and quantify contaminants, assess radiation exposures of members of the public, demonstrate compliance with applicable standards and permit requirements, and detect and assess the effects (if any) on the local environment. Multiple samples are collected throughout the year and are analyzed for radioactivity, chemical content, and various physical attributes

  8. Production of gaseous or vaporous fuels from solid carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    1951-05-16

    A process for the production of gaseous or vaporous fuels from solid carbonaceous materials consists of subjecting the materials in separate zones to at least three successive thermal treatments at least two of which are carried out at different temperature levels. The materials being maintained in zones in the form of beds of finely divided particles fluidized by the passage of gases or vapors upwardly there-through, and recovering product vapors or gases overhead. The total hot gaseous or vaporous effluent and entrained solids from one of the zones is passed directly without separation to another of the zones situated closely adjacent to and vertically above the first named zone in the same vessel, and the heat required in at least one of the thermal treatment zones is supplied at least in part as the sensible heat of residual solids transferred from a thermal treatment zone operated at a higher temperature.

  9. Aging phenomena in gaseous detectors - perspectives from the 2001 workshop

    CERN Document Server

    Hohlmann, M; Tesch, N; Titov, M

    2002-01-01

    High-Energy Physics experiments are currently entering a new era which requires the operation of gaseous particle detectors at unprecedented high rates and integrated particle fluxes. Full functionality of such detectors over the lifetime of an experiment in a harsh radiation environment is of prime concern. New classes of gaseous detectors such as large-scale straw-type detectors, Micro-pattern Gas Detectors, and resistive plate chambers--each with their own specific aging characteristics--have evolved since the first workshop on wire chamber aging was held at LBL, Berkeley in 1986. The 2001 workshop provided a forum to review the progress since 1986 in understanding aging effects and to exchange recent experiences. A summary of the main results reported at the 2001 workshop is presented providing a systematic review of aging effects in state-of-the-art detectors.

  10. Method of producing gaseous products using a downflow reactor

    Science.gov (United States)

    Cortright, Randy D; Rozmiarek, Robert T; Hornemann, Charles C

    2014-09-16

    Reactor systems and methods are provided for the catalytic conversion of liquid feedstocks to synthesis gases and other noncondensable gaseous products. The reactor systems include a heat exchange reactor configured to allow the liquid feedstock and gas product to flow concurrently in a downflow direction. The reactor systems and methods are particularly useful for producing hydrogen and light hydrocarbons from biomass-derived oxygenated hydrocarbons using aqueous phase reforming. The generated gases may find used as a fuel source for energy generation via PEM fuel cells, solid-oxide fuel cells, internal combustion engines, or gas turbine gensets, or used in other chemical processes to produce additional products. The gaseous products may also be collected for later use or distribution.

  11. Eddy covariance flux measurements of gaseous elemental mercury using cavity ring-down spectroscopy.

    Science.gov (United States)

    Pierce, Ashley M; Moore, Christopher W; Wohlfahrt, Georg; Hörtnagl, Lukas; Kljun, Natascha; Obrist, Daniel

    2015-02-03

    A newly developed pulsed cavity ring-down spectroscopy (CRDS) system for measuring atmospheric gaseous elemental mercury (GEM) concentrations at high temporal resolution (25 Hz) was used to successfully conduct the first eddy covariance (EC) flux measurements of GEM. GEM is the main gaseous atmospheric form, and quantification of bidirectional exchange between the Earth's surface and the atmosphere is important because gas exchange is important on a global scale. For example, surface GEM emissions from natural sources, legacy emissions, and re-emission of previously deposited anthropogenic pollution may exceed direct primary anthropogenic emissions. Using the EC technique for flux measurements requires subsecond measurements, which so far has not been feasible because of the slow time response of available instrumentation. The CRDS system measured GEM fluxes, which were compared to fluxes measured with the modified Bowen ratio (MBR) and a dynamic flux chamber (DFC). Measurements took place near Reno, NV, in September and October 2012 encompassing natural, low-mercury (Hg) background soils and Hg-enriched soils. During nine days of measurements with deployment of Hg-enriched soil in boxes within 60 m upwind of the EC tower, the covariance of GEM concentration and vertical wind speed was measured, showing that EC fluxes over an Hg-enriched area were detectable. During three separate days of flux measurements over background soils (without Hg-enriched soils), no covariance was detected, indicating fluxes below the detection limit. When fluxes were measurable, they strongly correlated with wind direction; the highest fluxes occurred when winds originated from the Hg-enriched area. Comparisons among the three methods showed good agreement in direction (e.g., emission or deposition) and magnitude, especially when measured fluxes originated within the Hg-enriched soil area. EC fluxes averaged 849 ng m(-2) h(-1), compared to DFC fluxes of 1105 ng m(-2) h(-1) and MBR fluxes

  12. Removing Gaseous NH3 Using Biochar as an Adsorbent

    Directory of Open Access Journals (Sweden)

    Kyoung S. Ro

    2015-09-01

    Full Text Available Ammonia is a major fugitive gas emitted from livestock operations and fertilization production. This study tested the potential of various biochars in removing gaseous ammonia via adsorption processes. Gaseous ammonia adsorption capacities of various biochars made from wood shaving and chicken litter with different thermal conditions and activation techniques were determined using laboratory adsorption column tests. Ammonia adsorption capacities of non-activated biochars ranged from 0.15 to 5.09 mg·N/g, which were comparable to that of other commercial activated carbon and natural zeolite. There were no significant differences in ammonia adsorption capacities of steam activated and non-activated biochars even if the surface areas of the steam activated biochars were about two orders of magnitude greater than that of non-activated biochars. In contrast, phosphoric acid activation greatly increased the biochar ammonia adsorption capacity. This suggests that the surface area of biochar did not readily control gaseous NH3 adsorption. Ammonia adsorption capacities were more or less linearly increased with acidic oxygen surface groups of non-activated and steam-activated biochars. Phosphoric acid bound to the acid activated biochars is suspected to contribute to the exceptionally high ammonia adsorption capacity. The sorption capacities of virgin and water-washed biochar samples were not different, suggesting the potential to regenerate spent biochar simply with water instead of energy- and capital-intensive steam. The results of this study suggest that non-activated biochars can successfully replace commercial activated carbon in removing gaseous ammonia and the removal efficiency will greatly increase if the biochars are activated with phosphoric acid.

  13. Interpretation of the [ClIII] Lines in Gaseous Nebulae.

    Science.gov (United States)

    Aller, L H; Czyzak, S J; Walker, M F; Krueger, T K

    1970-05-01

    The intensity ratio of the green lambdalambda5517 and 5537 lines of [ClIII] serves as an indicatrix of the electron density in many gaseous nebulae whose spectra can be observed with an image converter. Quantitative interpretation of the line ratio requires accurate values of the collisional strengths and transition probabilities. With improved values of these parameters we have revised electron densities for a number of nebulae; the results seem to be in good accord with those derived from other criteria.

  14. Demister apparatus for gaseous wastes carrying radioactive aerosols

    International Nuclear Information System (INIS)

    Meline, F.G.; Richter, R.J.

    1983-01-01

    In the nuclear industry, more precisely in the field of spent fuel reprocessing, the cleaning of the gaseous wastes, before evacuation, should be realized with a device designed in order to take full account of the constraints that are inherent in the radioactive media. The French Atomic Authority (CEA), in collaboration with the Societe Generale pour les Techniques Nouvelles, have studied and developed types of demister for the nuclear field having good cleaning properties

  15. Thermodynamic properties of cesium in the gaseous phase

    International Nuclear Information System (INIS)

    Vargaftik, N.B.; Voljak, L.D.; Stepanov, V.G.

    1985-01-01

    Tables of the thermodynamic properties of caesium in the gaseous phase are presented for a wide range of temperature and pressure. The thermodynamic properties include: enthalpy, entropy, specific heat, specific volume, sound velocity and compressibility factor. The values have been calculated from pressure-volume-temperature measurements by various authors. Experimental apparatus to determine these measurements is described, together with an outline of the method employed to process the results, and the error estimates. (U.K.)

  16. Method of removing iodine and compounds thereof from gaseous effluents

    International Nuclear Information System (INIS)

    Keener, R.L.; Kittle, P.A.

    1976-01-01

    Anion exchange resins including an acrylic backbone formed by the suspension polymerization of a mixture of an acrylic and a crosslinking monomer are useful in the removal of iodine and iodine compounds from gaseous effluents. Removal of radioactive iodine contaminants, particularly alkyl iodine compounds or hydrogen iodine, under extreme conditions, namely temperatures up to 180 0 C and humidities up to 100 percent, from effluents resulting from a major nuclear accident could probably be adsorbed by these resins described herein

  17. The Mass and Absorption Columns of Galactic Gaseous Halos

    Science.gov (United States)

    Qu, Zhijie; Bregman, Joel N.

    2018-01-01

    The gaseous halo surrounding the galaxy is a reservoir for the gas on the galaxy disk, supplying materials for the star formation. We developed a gaseous halo model connecting the galactic disk and the gaseous halo by assuming the star formation rate is equal to the radiative cooling rate. Besides the single-phase collisional gaseous halo, we also consider the photoionization effect and a time-independent cooling model that assumes the mass cooling rate is constant over all temperatures. The photoionization dominates the low mass galaxy and the outskirts of the massive galaxy due to the low-temperature or low-density nature. The multi-phase cooling model dominates the denser region within the cooling radius, where the efficient radiative cooling must be included. Applying these two improvements, our model can reproduce the most of observed high ionization state ions (i.e., O VI, O VII, Ne VIII and Mg X). Our models show that the O VI column density is almost a constant of around 10^14 cm^-2 over a wide stellar mass from M_\\star ~10^8 M_Sun to 10^11 M_Sun, which is constant with current observations. This model also implies the O VI is photoionized for the galaxy with a halo mass fraction function of the EAGLE simulation. Finally, our model predicts plateaus of the Ne VIII and the Mg X column densities above the sub-L^* galaxy, and the possibly detectable O VII and O VIII column densities for low-mass galaxies, which help to determine the required detection limit for the future observations and missions.

  18. Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau

    Directory of Open Access Journals (Sweden)

    A. Dommergue

    2012-11-01

    Full Text Available Gaseous elemental mercury (Hg0 was investigated in the troposphere and in the interstitial air extracted from the snow at Dome Concordia station (alt. 3320 m on the Antarctic Plateau during January 2009. Measurements and modeling studies showed evidence of a very dynamic and daily cycling of Hg0 inside the mixing layer with a range of values from 0.2 ng m−3 up to 2.3 ng m−3. During low solar irradiation periods, fast Hg0 oxidation processes in a confined layer were suspected. Unexpectedly high Hg0 concentrations for such a remote place were measured under higher solar irradiation due to snow photochemistry. We suggest that a daily cycling of reemission/oxidation occurs during summer within the mixing layer at Dome Concordia. Hg0 concentrations showed a negative correlation with ozone mixing ratios, which contrasts with atmospheric mercury depletion events observed during the Arctic spring. Unlike previous Antarctic studies, we think that atmospheric Hg0 removal may not be the result of advection processes. The daily and dramatic Hg0 losses could be a consequence of surface or snow induced oxidation pathways. It remains however unclear whether halogens are involved. The cycling of other oxidants should be investigated together with Hg species in order to clarify the complex reactivity on the Antarctic plateau.

  19. Dissolved gaseous mercury and mercury flux measurements in Mediterranean coastal waters: A short review

    Directory of Open Access Journals (Sweden)

    Fantozzi L.

    2013-04-01

    Full Text Available There is a general agreement in the scientific community that the marine ecosystem can be a sink and/or source of the mercury that is cycling in the global environment, and current estimates of the global mercury budget for the Mediterranean region are affected by high uncertainty, primarily due to the little progress made so far in evaluating the role of chemical, physical and biological processes in the water system and in the lower atmosphere above the sea water (air-water interface. The lack of knowledge of the magnitude of the air-sea exchange mechanisms is, therefore, one of the main factors affecting the overall uncertainty associated with the assessment of net fluxes of Hg between the atmospheric and marine environments in the Mediterranean region. Results obtained during the last 15 years in the Mediterranean basin indicate the quantitative importance of such emission in the biogeochemical cycle of this element, highlighting the need for thorough investigations on the mechanisms of production and volatilization of dissolved gaseous mercury in waters.

  20. Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions

    Science.gov (United States)

    Li, Guo; Su, Hang; Li, Xin; Kuhn, Uwe; Meusel, Hannah; Hoffmann, Thorsten; Ammann, Markus; Pöschl, Ulrich; Shao, Min; Cheng, Yafang

    2016-08-01

    Gaseous formaldehyde (HCHO) is an important precursor of OH radicals and a key intermediate molecule in the oxidation of atmospheric volatile organic compounds (VOCs). Budget analyses reveal large discrepancies between modeled and observed HCHO concentrations in the atmosphere. Here, we investigate the interactions of gaseous HCHO with soil surfaces through coated-wall flow tube experiments applying atmospherically relevant HCHO concentrations of ˜ 10 to 40 ppbv. For the determination of uptake coefficients (γ), we provide a Matlab code to account for the diffusion correction under laminar flow conditions. Under dry conditions (relative humidity = 0 %), an initial γ of (1.1 ± 0.05) × 10-4 is determined, which gradually drops to (5.5 ± 0.4) × 10-5 after 8 h experiments. Experiments under wet conditions show a smaller γ that drops faster over time until reaching a plateau. The drop of γ with increasing relative humidity as well as the drop over time can be explained by the adsorption theory in which high surface coverage leads to a reduced uptake rate. The fact that γ stabilizes at a non-zero plateau suggests the involvement of irreversible chemical reactions. Further back-flushing experiments show that two-thirds of the adsorbed HCHO can be re-emitted into the gas phase while the residual is retained by the soil. This partial reversibility confirms that HCHO uptake by soil is a complex process involving both adsorption/desorption and chemical reactions which must be considered in trace gas exchange (emission or deposition) at the atmosphere-soil interface. Our results suggest that soil and soil-derived airborne particles can either act as a source or a sink for HCHO, depending on ambient conditions and HCHO concentrations.

  1. Gas phase decontamination of gaseous diffusion process equipment

    International Nuclear Information System (INIS)

    Bundy, R.D.; Munday, E.B.; Simmons, D.W.; Neiswander, D.W.

    1994-01-01

    D ampersand D of the process facilities at the gaseous diffusion plants (GDPs) will be an enormous task. The EBASCO estimate places the cost of D ampersand D of the GDP at the K-25 Site at approximately $7.5 billion. Of this sum, nearly $4 billion is associated with the construction and operation of decontamination facilities and the dismantlement and transport of contaminated process equipment to these facilities. In situ long-term low-temperature (LTLT) gas phase decontamination is being developed and demonstrated at the K-25 site as a technology that has the potential to substantially lower these costs while reducing criticality and safeguards concerns and worker exposure to hazardous and radioactive materials. The objective of gas phase decontamination is to employ a gaseous reagent to fluorinate nonvolatile uranium deposits to form volatile LJF6, which can be recovered by chemical trapping or freezing. The LTLT process permits the decontamination of the inside of gas-tight GDP process equipment at room temperature by substituting a long exposure to subatmospheric C1F for higher reaction rates at higher temperatures. This paper outlines the concept for applying LTLT gas phase decontamination, reports encouraging laboratory experiments, and presents the status of the design of a prototype mobile system. Plans for demonstrating the LTLT process on full-size gaseous diffusion equipment are also outlined briefly

  2. Photodetachment in the gaseous, liquid, and solid states of matter

    International Nuclear Information System (INIS)

    Christophorou, L.G.; Datskos, P.G.; Faidas, H.

    1994-01-01

    We have made absolute cross section measurements of laser photodetachment of C 6 F - 6 ions embedded in gaseous tetramethylsilane (TMS) and compared the results at low gas densities with measurements in nonpolar liquids and solids. The measurements indicate that the photodetachment cross section of C 6 F - 6 in gaseous TMS is about three times larger than in liquid TMS. This is rationalized by considering the effect of the medium on both the photoabsorption and the autodetachment processes. The photodetachment cross section in both the gas and the liquid exhibits (at least) two maxima due to autodetaching negative ion states. It is argued that these are due to σ*→σ* transitions in C 6 F - 6 . The relative positions of these ''superexcited'' anionic states did not change appreciably in going from the gas to the liquid and the solid, indicating similar influences of the medium on them. As expected, the photodetachment threshold in the condensed phase is shifted to higher energies compared to the gaseous phase. This shift is consistent with recent photoelectron studies of photodetachment of C 6 F - 6 clusters. The present study clearly shows that the photodetachment from negative ions embedded in all states of matter proceeds directly or indirectly via negative ion autodetaching states, and that for nonpolar media, the effect of the medium can be accounted for by considering the macroscopic properties of the medium described by its dielectric constant ε and refractive index n

  3. Measurements of gaseous multiplication coefficient in pure isobutane

    International Nuclear Information System (INIS)

    Lima, Iara Batista de

    2010-01-01

    In this work it is presented measurements of gaseous multiplication coefficient (α) in pure isobutane obtained with a parallel plate chamber, protected against discharges by one electrode (anode) of high resistivity glass (ρ = 2 x 10 12 Ω.cm). The method applied was the Pulsed Townsend, where the primary ionization is produced through the incidence of a nitrogen laser beam onto a metallic electrode (cathode). The electric currents measured with the chamber operating in both ionization and avalanche regimes were used to calculate the gaseous multiplication coefficient by the solution of the Townsend equation for uniform electric fields. The validation of the technique was provided by the measurements of gaseous multiplication coefficient in pure nitrogen, a widely studied gas, which has well-established data in literature. The α coefficients in isobutane were measured as a function of the reduced electric field in the range of 139Td up to 208Td. The obtained values were compared with those simulated by Imonte software (version 4.5) and the only experimental results available in the literature, recently obtained in our group. This comparison showed that the results are concordant within the experimental errors. (author)

  4. Separation of tritium from gaseous and aqueous effluent systems

    International Nuclear Information System (INIS)

    Kobisk, E.H.

    1977-01-01

    Removal or reduction of tritium content in a wide variety of effluent streams has been extensively studied in the United States. This paper specifically reviews three processes involving tritium separation in the gaseous phase and the aqueous phase. Diffusion through a selective Pd-25Ag alloy membrane at temperatures up to 600 0 C and at pressures up to 700 kg/cm 2 has resulted in successful separation of hydrogen-deuterium mixtures with an associated separation factor of 1.65 (and gives a calculated separation factor for hydrogen-tritium mixtures of 2.0). Use of a single palladium bipolar membrane in an electrolysis system has been found to yield a hydrogen-deuterium separation factor of 4 and a hydrogen-tritium factor of 6 to 11 without the production of gaseous hydrogen. Finally, countercurrent catalytic exchange between tritium-containing hydrogen gas and water has yielded a separation factor of 6.3. The specific advantages of each of these systems will be discussed in terms of their potential applications. In all cases, further investigations are necessary to scale the systems to handle large quantities of feed material in a continuous mode and to minimize energy requirements. Such separative systems must necessarily be cascaded to yield gaseous or aqueous product streams suitable for recycling to the tritium producing systems, for storage or for discharge to the environment. (orig./HP) [de

  5. Monitoring and removal of gaseous carbon-14 species

    International Nuclear Information System (INIS)

    Kabat, M.J.

    1979-01-01

    A simple and efficient method was developed for the monitoring of low level carbon-14 in nuclear power station areas and gaseous effluent. Gaseous carbon compounds (hydrocarbons and CO) are catalytically oxidized to CO 2 , which is then absorbed on solid Ca(OH) 2 at elevated temperatures. The 14 C collected is quantitatively liberated by thermal decomposition of CaCO 3 as CO 2 , which is either measured directly by flow-through detectors or absorbed in alkali hydroxide followed by liquid scintillation counting. The method can also be used for the removal of gaseous 14 C. The Ca 14 CO 3 can be immobilized in concrete for long term disposal. Ca(OH) 2 is an inexpensive absorber. It is selective for CO 2 and has high capacity and efficiency for its absorption and retention. A theoretical evaluation of thee optium conditions for CO 2 absorption and liberation is discussed and experimental investigations are described. There is good agreement between theoretical predictions and experimental findings

  6. Evaluation of leafy vegetables as bioindicators of gaseous mercury pollution in sewage-irrigated areas.

    Science.gov (United States)

    Zheng, Shun-An; Wu, Zeying; Chen, Chun; Liang, Junfeng; Huang, Hongkun; Zheng, Xiangqun

    2018-01-01

    Mercury (Hg) can evaporate and enter the plants through the stomata of plant leaves, which will cause a serious threat to local food safety and human health. For the risk assessment, this study aimed to investigate the concentration and accumulation of total gaseous mercury (TGM) in five typical leafy vegetables (Chinese chives (Allium tuberosum Rottler), amaranth (Amaranthus mangostanus L.), rape (Brassica campestris L.), lettuce (Lactuca sativa L.), and spinach (Spinacia oleracea L.)) grown on sewage-irrigated areas in Tianjin, China. The following three sites were chosen to biomonitor Hg pollution: a paddy field receiving sewage irrigation (industrial and urban sewage effluents) for the last 30 years, a vegetable field receiving sewage irrigation for 15 years, and a grass field which did not receive sewage irrigation in history. Results showed that the total Hg levels in the paddy (0.65 mg kg -1 ) and vegetation fields (0.42 mg kg -1 ) were significantly higher than the local background level (0.073 mg kg -1 ) and the China national soil environment quality standard for Hg in grade I (0.30 mg kg -1 ). The TGM levels in ambient air were significantly higher in the paddy (71.3 ng m -3 ) and vegetable fields (39.2 ng m -3 ) relative to the control (9.4 ng m -3 ) and previously reported levels (1.45 ng m -3 ), indicating severe Hg pollution in the atmospheric environment of the sewage-irrigated areas. Furthermore, gaseous mercury was the dominant form of Hg uptake in the leaves or irreversibly bound to leaves. The comparison of Hg uptake levels among the five vegetables showed that the gradient of Hg accumulation followed the order spinach > red amaranth > Chinese chives > rape > lettuce. These results suggest that gaseous Hg exposure in the sewage-irrigated areas is a dominant Hg uptake route in leafy vegetables and may pose a potential threat to agricultural food safety and human health.

  7. Evaluation of passive sampling of gaseous mercury using different sorbing materials.

    Science.gov (United States)

    Lin, Huiming; Zhang, Wei; Deng, Chunyan; Tong, Yingdong; Zhang, Qianggong; Wang, Xuejun

    2017-06-01

    Atmospheric mercury monitoring is essential because of its potential human health and ecological impacts. Current automated monitoring systems include limitations such as high cost, complicated configuration, and electricity requirements. Passive samplers require no electric power and are more appropriate for screening applications and long-term monitoring. Sampling rate is a major factor to evaluate the performance of a passive sampler. In this study, laboratory experiments were carried out using an exposure chamber to search for high efficiency sorbents for gaseous mercury. Four types of sorbents, including sulfur-impregnated carbon (SIC), chlorine-impregnated carbon (CIC), bromine-impregnated carbon (BIC), and gold-coated sand (GCS) were evaluated under a wide range of meteorological parameters, including temperature, relative humidity, and wind speed. The results showed that the four sorbents all have a high sampling rate above 0.01 m 3 g -1  day -1 , and wind speed has a positive correlation with the sampling rate. Under different temperature and relative humidity, the sampling rate of SIC keeps stable. The sampling rate of CIC and BIC shows a negative correlation with temperature, and GCS is influenced by all the three meteorological factors. Furthermore, long-term experiments were carried out to investigate the uptake capacity of GCS and SIC. Uptake curves show that the mass amount of sorbent in a passive sampler can influence uptake capacity. In the passive sampler, 0.9 g SIC or 0.9 g GCS can achieve stable uptake efficiency for at least 110 days with gaseous mercury concentration at or below 2 ng/m 3 . For mercury concentration at or below 21 ng/m 3 , 0.9 g SIC can maintain stable uptake efficiency for 70 days, and 0.9 g GCS can maintain stability for 45 days.

  8. Uptake of gaseous formaldehyde onto soil surfaces: a coated-wall flow tube study

    Science.gov (United States)

    Li, Guo; Su, Hang; Li, Xin; Meusel, Hannah; Kuhn, Uwe; Pöschl, Ulrich; Shao, Min; Cheng, Yafang

    2015-04-01

    Gaseous formaldehyde (HCHO) is an important intermediate molecule and source of HO2 radicals. However, discrepancies exist between model simulated and observed HCHO concentrations, suggesting missing sources or sinks in the HCHO budget. Multiphase processes on the surface of soil and airborne soil-derived particles have been suggested as an important mechanism for the production/removal of atmospheric trace gases and aerosols. In this work, the uptake of gaseous HCHO on soil surfaces were investigated through coated-wall flow tube experiments with HCHO concentration ranging from 10 to 40 ppbv. The results show that the adsorption of HCHO occurred on soil surfaces, and the uptake coefficient dropped gradually (i.e., by a factor of 5 after 1 hour) as the reactive surface sites were consumed. The HCHO uptake coefficient was found to be affected by the relative humidity (RH), decreasing from (2.4 ± 0.5) × 10-4 at 0% RH to (3.0 ± 0.08) × 10-5 at 70% RH, due to competition of water molecule absorption on the soil surface. A release of HCHO from reacted soil was also detected by applying zero air, suggesting the nature of reversible physical absorption and the existence of an equilibrium at the soil-gas interface. It implies that soil could be either a source or a sink for HCHO, depending on the ambient HCHO concentration. We also develop a Matlab program to calculate the uptake coefficient under laminar flow conditions based on the Cooney-Kim-Davis method.

  9. Characteristics of total gaseous mercury concentrations at a coastal area of the Yangtze Delta, China.

    Science.gov (United States)

    Diao, Chunyan; Li, Jianfeng; Zhang, Bin; Tang, Shichuang

    2017-03-01

    In this study, we report on total gaseous mercury (TGM) field observations made in the rural area of Shanghai, Chongming Island, China, from September 2009 to April 2012. The average TGM was 2.65 ± 1.73 ng m -3 in Chongming Island, which is higher than the TGM background value of the Northern Hemisphere (1.5-1.7 ng m -3 ); this indicates that to some extent, the Chongming area has been affected by anthropogenic mercury emissions. The observed TGM follows a seasonal pattern; concentrations are highest in winter, followed by autumn, summer, and spring. There is also a clear diurnal variation in TGM. All peak values appear between 7:00 and 9:00 in all four seasons; this appears to be the result of the height change in the atmospheric boundary layer that occurs between day and night. TGM concentrations in Chongming remain high in the westerly wind direction, especially in the southwest direction because of its low frequency, so the greatest source contribution to TGM in Chongming lies to the northwest. Wind speed is also a significant factor affecting TGM, and was negatively correlated with TGM concentrations. TGM is also closely related to carbon monoxide (CO) concentrations, indicating that TGM is impacted by human activities. The slope of the linear fitting of TGM and CO demonstrates that the contribution of noncoal source emissions to TGM in summer is greater than in autumn, mainly because the high temperature and intensive sunlight in summer increase mercury emissions from natural sources. Except for some studies in the coastal areas (e.g., Kang Hwa Island by Kim et al., 2006, An-Myun Island by Kim et al., 2002, and Okinawa by Chan et al., 2008), data specifically for coastal areas are lacking. Monitoring of total gaseous mercury (TGM) in the rural area of Shanghai, Chongming Island, can help us understand mercury distribution.

  10. Air--sea gaseous exchange of PCB at the Venice lagoon (Italy).

    Science.gov (United States)

    Manodori, L; Gambaro, A; Moret, I; Capodaglio, G; Cescon, P

    2007-10-01

    Water bodies are important storage media for persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) and this function is increased in coastal regions because their inputs are higher than those to the open sea. The air-water interface is extensively involved with the global cycling of PCBs because it is the place where they accumulate due to depositional processes and where they may be emitted by gaseous exchange. In this work the parallel collection of air, microlayer and sub-superficial water samples was performed in July 2005 at a site in the Venice lagoon to evaluate the summer gaseous flux of PCBs. The total concentration of PCBs (sum of 118 congeners) in air varies from 87 to 273 pg m(-3), whereas in the operationally defined dissolved phase of microlayer and sub-superficial water samples it varies from 159 to 391 pg L(-1). No significant enrichment of dissolved PCB into the microlayer has been observed, although a preferential accumulation of most hydrophobic congeners occurs. Due to this behaviour, we believe that the modified two-layer model was the most suitable approach for the evaluation of the flux at the air-sea interface, because it takes into account the influence of the microlayer. From its application it appears that PCB volatilize from the lagoon waters with a net flux varying from 58 to 195 ng m(-2)d(-1) (uncertainty: +/-50-64%) due to the strong influence of wind speed. This flux is greater than those reported in the literature for the atmospheric deposition and rivers input and reveals that PCB are actively emitted from the Venice lagoon in summer months.

  11. Dry deposition of gaseous radioiodine and particulate radiocaesium onto leafy vegetables

    International Nuclear Information System (INIS)

    Tschiersch, Jochen; Shinonaga, Taeko; Heuberger, Heidi

    2009-01-01

    Radionuclides released to the atmosphere during dry weather (e.g. after a nuclear accident) may contaminate vegetable foods and cause exposure to humans via the food chain. To obtain experimental data for an appropriate assessment of this exposure path, dry deposition of radionuclides to leafy vegetables was studied under homogeneous and controlled greenhouse conditions. Gaseous 131 I-tracer in predominant elemental form and particulate 134 Cs-tracer at about 1 μm diameter were used to identify susceptible vegetable species with regard to contamination by these radionuclides. The persistence was examined by washing the harvested product with water. The vegetables tested were spinach (Spinacia oleracea), butterhead lettuce (Lactuca sativa var. capitata), endive (Cichorium endivia), leaf lettuce (Lactuca sativa var. crispa), curly kale (Brassica oleracea convar. acephala) and white cabbage (Brassica oleracea convar. capitata). The variation of radionuclides deposited onto each vegetable was evaluated statistically using the non-parametric Kruskal-Wallis Test and the U-test of Mann-Whitney. Significant differences in deposited 131 I and 134 Cs activity concentration were found among the vegetable species. For 131 I, the deposition velocity to spinach normalized to the biomass of the vegetation was 0.5-0.9 cm 3 g -1 s -1 which was the highest among all species. The particulate 134 Cs deposition velocity of 0.09 cm 3 g -1 s -1 was the highest for curly kale, which has rough and structured leaves. The lowest deposition velocity was onto white cabbage: 0.02 cm 3 g -1 s -1 (iodine) and 0.003 cm 3 g -1 s -1 (caesium). For all species, the gaseous iodine deposition was significantly higher compared to the particulate caesium deposition. The deposition depends on the sensitive parameters leaf area, stomatal aperture, and plant morphology. Decontamination by washing with water was very limited for iodine but up to a factor of two for caesium.

  12. Modelization and numerical simulation of atmospheric aerosols dynamics

    International Nuclear Information System (INIS)

    Debry, Edouard

    2004-01-01

    Chemical-transport models are now able to describe in a realistic way gaseous pollutants behavior in the atmosphere. Nevertheless atmospheric pollution also exists as a fine suspended particles, called aerosols which interact with gaseous phase, solar radiation, and have their own dynamic behavior. The goal of this thesis is the modelization and numerical simulation of the General Dynamic Equation of aerosols (GDE). Part I deals with some theoretical aspects of aerosol modelization. Part II is dedicated to the building of one size resolved aerosol model (SIREAM). In part III we perform the reduction of this model in order to use it in dispersion models as POLAIR3D. Several modelization issues are still opened: organic aerosol matter, externally mixed aerosols, coupling with turbulent mixing, and nano-particles. (author) [fr

  13. Vertical profile measurements of soil air suggest immobilization of gaseous elemental mercury in mineral soil.

    Science.gov (United States)

    Obrist, Daniel; Pokharel, Ashok K; Moore, Christopher

    2014-02-18

    Evasion of gaseous elemental Hg (Hg(0)g) from soil surfaces is an important source of atmospheric Hg, but the volatility and solid-gas phase partitioning of Hg(0) within soils is poorly understood. We developed a novel system to continuously measure Hg(0)g concentrations in soil pores at multiple depths and locations, and present a total of 297 days of measurements spanning 14 months in two forests in the Sierra Nevada mountains, California, U.S. Temporal patterns showed consistent pore Hg(0)g concentrations below levels measured in the atmosphere (termed Hg(0)g immobilization), ranging from 66 to 94% below atmospheric concentrations throughout multiple seasons. The lowest pore Hg(0)g concentrations were observed in the deepest soil layers (40 cm), but significant immobilization was already present in the top 7 cm. In the absence of sinks or sources, pore Hg(0)g levels would be in equilibrium with atmospheric concentrations due to the porous nature of the soil matrix and gas diffusion. Therefore, we explain decreases in pore Hg(0)g in mineral soils below atmospheric concentrations--or below levels found in upper soils as observed in previous studies--with the presence of an Hg(0)g sink in mineral soils possibly related to Hg(0)g oxidation or other processes such as sorption or dissolution in soil water. Surface chamber measurements showing daytime Hg(0)g emissions and nighttime Hg(0)g deposition indicate that near-surface layers likely dominate net atmospheric Hg(0)g exchange resulting in typical diurnal cycles due to photochemcial reduction at the surface and possibly Hg(0)g evasion from litter layers. In contrast, mineral soils seem to be decoupled from this surface exchange, showing consistent Hg(0)g uptake and downward redistribution--although our calculations indicate these fluxes to be minor compared to other mass fluxes. A major implication is that once Hg is incorporated into mineral soils, it may be unlikely subjected to renewed Hg(0)g re-emission from

  14. Pluto's surface composition and atmosphere

    Science.gov (United States)

    Young, L. A.; Gladstone, R.; Summers, M. E.; Strobel, D. F.; Kammer, J.; Hinson, D. P.; Grundy, W. M.; Cruikshank, D. P.; Protopapa, S.; Schmitt, B.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.

    2017-12-01

    New Horizons studied Pluto's N2-dominated neutral atmosphere through radio (at 4.2 cm with the REX radio experiment), solar and stellar occultations and airglow (at 52-187 nm with the Alice ultraviolet spectrograph), and imaging (with the LORRI and MVIC visible-wavelength cameras). It studied the plasma environment and solar wind interaction with in situ instruments (PEPPSI and SWAP). Contemporaneous observations of Pluto's atmosphere from Earth included a ground-based stellar occultation and ALMA observations of gaseous CO and HCN. Joint analysis of these datasets reveal a variable boundary layer; a stable lower atmosphere; radiative heating and cooling; haze production and hydrocarbon chemistry; diffusive equilibrium; and slower-than-expected escape. New Horizons studied Pluto's surface composition with the LEISA near-infrared spectral imager from 1.25 to 2.5 micron. Additional compositional information at higher spatial resolution came from the MVIC 4-channel color imager, which included a channel centered at 0.89 micron specifically designed to detect solid CH4. These instruments allow mapping of the volatiles N2, CO, and CH4, the surface expression of the H2O bedrock, and the dark, reddish material presumed to be tholins. These observations reveal a large equatorial basin (informally named Sptunik Planitia), filled with N2 ice with minor amounts of CO and CH4, surrounded by hills of CH4 and H2O ice. Broadly speaking, composition outside of Sptunik Planitia follows latitudinal banding, with dark, mainly volatile free terrains near the equator, with N2, CO, and CH4 at mid-northern latitudes, and mainly CH4 at high northern latitudes. Deviations from these broad trends are seen, and point to complex surface-atmosphere interactions at diurnal, seasonal, perennial, and million-year timescales.

  15. Understanding Microbial Contributions to Planetary Atmosphere

    Science.gov (United States)

    DesMarais, David J.

    2000-01-01

    Should our search of distant, extrasolar planetary atmospheres encounter evidence of life, that evidence will most likely be the gaseous products of microorganisms. Our biosphere was exclusively microbial for over 80 percent of its history and, even today, microbes strongly influence atmospheric composition. Life's greatest environmental impact arises from its capacity for harvesting energy and creating organic matter. Microorganisms catalyze the equilibration of C, S and transition metal species at temperatures where such reactions can be very slow in the absence of life. Sunlight has been harvested through photosynthesis to create enormous energy reservoirs that exist in the form of coexisting reservoirs of reduced, organic C and S stored in Earth's crust, and highly oxidized species (oxygen, sulfate and ferric iron) stored in the crust, oceans and atmosphere. Our civilization taps that storehouse of energy by burning fossil fuels. As astrobiologists, we identify the chemical consequences of distant biospheres as expressed in the atmospheres of their planets. Our approach must recognize that planets, biospheres and atmospheres evolve and change. For example, a tectonically more active early Earth hosted a thermophilic, non-photosynthetic biosphere and a mildly reducing, carbon dioxide-rich and oxygen-poor atmosphere. Microorganisms acquired energy by consuming hydrogen and sulfide and producing a broad array of reduced C and S gases, most notably, methane. Later, diverse types of bacterial photosynthesis developed that enhanced productivity but were incapable of splitting water to produce oxygen. Later, but still prior to 2.6 billion years ago, oxygenic photosynthesis developed. We can expect to encounter distant biospheres that represent various stages of evolution and that coexist with atmospheres ranging from mildly reducing to oxidizing compositions. Accordinaly, we must be prepared to interpret a broad range of atmospheric compositions, all containing

  16. Usage Proposal of a common urban decorative tree (Salix alba L.) to monitor the dispersion of gaseous mercury: A case study from Turda (Romania).

    Science.gov (United States)

    Esbrí, J M; Cacovean, H; Higueras, P

    2018-02-01

    Closure of chloralkali plants poses a risk of abandonment of important sources of gaseous mercury. In this work, an assessment has been made of the potential for pollution from one of these plants in the proximity of a densely populated town in central Romania. The work involved a comparison between two major types of monitoring survey: biomonitoring using leaves of a tree common in urban environments; and LUMEX-based gaseous mercury analysis. For biomonitoring, 21 samples from Salix alba L. trees were taken in Turda area. Atmospheric monitoring included two mobile surveys and one at a fixed location. The results from both monitoring systems show similarities in gaseous mercury dispersion patterns, with high mercury contents clearly related to the presence of the chloralkali plant. Particularly high levels were measured in the following situations: (i) in a 'smog' area related with thermal inversion and (ii) during dusk. Direct monitoring suffered from limitations in acquiring information, especially in a medium-long time range, but biomonitoring provided these data and is capable of covering studies on temporary trends or comparative assessments between European cities with contrasting gaseous mercury sources. The thermal speciation of mercury contents indicates that the whole fraction of mercury in leaves corresponds to organic mercury. This finding implies a non-reversible uptake process, which in turn ensures the applicability of this technique to biomonitor long-term exposure. As a conclusion, the assessment of gaseous mercury pollution based on biomonitoring using S. alba has proven to be a useful, reliable and cost-effective methodology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Composition, Chemistry, and Climate of the Atmosphere. 2: Mean properties of the atmosphere

    Science.gov (United States)

    Singh, Hanwant B. (Editor); Salstein, David A.

    1994-01-01

    The atmosphere can be defined as the relatively thin gaseous envelope surrounding the entire planet Earth. It possesses a number of properties related to its physical state and chemical composition, and it undergoes a variety of internal processes and external interactions that can either maintain or alter these properties. Whereas descriptions of the atmosphere's chemical properties form much of the remaining chapters of this book, the present chapter will highlight the atmosphere's gases, and these define its temperature structure. In contrast, the larger-scale motions comprise the winds, the global organization of which is often referred to as the general circulation. The framework of the dynamical and thermodynamical laws, including the three principles of conversation of mass, momentum, and energy, are fundamental in describing both the internal processes of the atmosphere and its external interactions. The atmosphere is not a closed system, because it exchanges all three of these internally conservative quantities across the atmosphere's boundary below and receives input from regions outside it. Thus surface fluxes of moisture, momentum, and heat occur to and from the underlying ocean and land. The atmosphere exchanges very little mass and momentum with space, though it absorbs directly a portion of the solar radiational energy received from above.

  18. Uptake of gaseous formaldehyde by soil surfaces: a combination of adsorption/desorption equilibrium and chemical reactions

    Directory of Open Access Journals (Sweden)

    G. Li

    2016-08-01

    Full Text Available Gaseous formaldehyde (HCHO is an important precursor of OH radicals and a key intermediate molecule in the oxidation of atmospheric volatile organic compounds (VOCs. Budget analyses reveal large discrepancies between modeled and observed HCHO concentrations in the atmosphere. Here, we investigate the interactions of gaseous HCHO with soil surfaces through coated-wall flow tube experiments applying atmospherically relevant HCHO concentrations of  ∼  10 to 40 ppbv. For the determination of uptake coefficients (γ, we provide a Matlab code to account for the diffusion correction under laminar flow conditions. Under dry conditions (relative humidity  =  0 %, an initial γ of (1.1 ± 0.05  ×  10−4 is determined, which gradually drops to (5.5 ± 0.4  ×  10−5 after 8 h experiments. Experiments under wet conditions show a smaller γ that drops faster over time until reaching a plateau. The drop of γ with increasing relative humidity as well as the drop over time can be explained by the adsorption theory in which high surface coverage leads to a reduced uptake rate. The fact that γ stabilizes at a non-zero plateau suggests the involvement of irreversible chemical reactions. Further back-flushing experiments show that two-thirds of the adsorbed HCHO can be re-emitted into the gas phase while the residual is retained by the soil. This partial reversibility confirms that HCHO uptake by soil is a complex process involving both adsorption/desorption and chemical reactions which must be considered in trace gas exchange (emission or deposition at the atmosphere–soil interface. Our results suggest that soil and soil-derived airborne particles can either act as a source or a sink for HCHO, depending on ambient conditions and HCHO concentrations.

  19. A study of reactions of sulfur dioxide in the gaseous phase. Production and evolution of aerosols resulting from these reactions

    International Nuclear Information System (INIS)

    Boulaud, Denis

    1977-01-01

    The reactions of sulfur dioxide in the gaseous phase with atmospheric pollutants (NO x ; hydrocarbons) were studied. Experiments showed that NO 2 contribution was significant and suggested that SO 2 transformation into sulfuric acid and sulfates might occur through oxidising agents mainly hydroxyl (OH) and hydro-peroxyl (HO 2 ) radicals. The production and evolution of the resulting aerosols was also studied. It was demonstrated that the effect of water vapour on particle production was significant and that primary embryos were formed from the hetero-molecular homogeneous nucleation acting on water vapour and very likely on sulfuric acid. There was a semi-quantitative agreement between our experimental results and some theoretical investigations on nucleation rate of the system (H 2 O - H 2 SO 4 ). The subsequent growth of particles was studied in a simulation chamber. Finally a model of sulfuric acid vapour evolution in presence of atmospheric aerosols made it possible to extend the previous results as far as possible to the case of atmosphere and then to compare the importance of homogeneous and heterogeneous nucleation of the vapours according to atmospheric conditions. (author) [fr

  20. Radiocarbon measurements of small gaseous samples at CologneAMS

    Science.gov (United States)

    Stolz, A.; Dewald, A.; Altenkirch, R.; Herb, S.; Heinze, S.; Schiffer, M.; Feuerstein, C.; Müller-Gatermann, C.; Wotte, A.; Rethemeyer, J.; Dunai, T.

    2017-09-01

    A second SO-110 B (Arnold et al., 2010) ion source was installed at the 6 MV CologneAMS for the measurement of gaseous samples. For the gas supply a dedicated device from Ionplus AG was connected to the ion source. Special effort was devoted to determine optimized operation parameters for the ion source, which give a high carbon current output and a high 14C- yield. The latter is essential in cases when only small samples are available. Additionally a modified immersion lens and modified target pieces were tested and the target position was optimized.

  1. Gas dynamics models for an oscillating gaseous core fission reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kuijper, J.C.; Dam, H. van; Hoogenboom, J.E. (Interuniversitair Reactor Inst., Delft (Netherlands))

    1991-01-01

    Two one-dimensional models are developed for the investigation of the gas dynamical behaviour of the fuel gas in a cylindrical gaseous core fission reactor. By numerical and analytical calculations, it is shown that, for the case where a direct energy extraction mechanism (such as magneto-hydrodynamics (MHD)) is not present, increasing density oscillations occur in the gas. Also an estimate is made of the attainable direct energy conversion efficiency, for the case where a direct energy extraction mechanism is present. (author).

  2. Removing gaseous contaminants in 3He by cryogenic stripping

    International Nuclear Information System (INIS)

    Benapfl, M.; Biltoft, P.; Coombs, A.

    1995-01-01

    The Tritium Operations Group at LLNL, Tritium Facility has recently developed a 3 He recovery system to remove argon, xenon, neon, hydrogen, and all other contaminants from the 3 He stream in an Accelerator Production of Tritium (APT) experimental apparatus. In this paper the authors will describe in detail the background information, technical requirements, the design approach, and the results of their experimental tests. The authors believe this gas purification system may have other applications as it provides at a reasonable cost an efficient method for purification of gaseous helium

  3. The SLAC high-density gaseous polarized 3He target

    International Nuclear Information System (INIS)

    Johnson, J.R.; Chupp, T.E.; Smith, T.B.; Cates, G.D.; Driehuys, B.; Middleton, H.; Newbury, N.R.; Hughes, E.W.; Meyer, W.

    1995-01-01

    A large-scale high-pressure gaseous 3 He polarized target has been developed for use with a high-intensity polarized electron beam at the Stanford Linear Accelerator Center. This target was used successfully in an experiment to study the spin structure of the neutron. The target provided an areal density of about 7x10 21 nuclei/cm 2 and operated at 3 He polarizations between about 30% and 40% for the six-week duration of the experiment. ((orig.))

  4. Spectrophotometric determination of volautile inorganic hydrides in binary gaseous mixtures

    International Nuclear Information System (INIS)

    Rezchikov, V.G.; Skachkova, I.N.; Kuznetsova, T.S.; Khrushcheva, V.V.

    1985-01-01

    A study was made on possibility of single and continuons analysis of binary mixtures (hydride-gas) for the content of volatile inorganic hydrides (VIH) from absorption spectra in the 185-280 nm band. Dependences of the percentage of VIH transmission on the wavelength are presented. It is shown that the maximum of their absorption depends on the element-hydrogen the bond length and binding energy. Detection limit for boron hydride was established to be n x 10 -3 % vol at 185-190 nm wavelength. Technique for spectrophotometric hydride determination in binary mixtures with hydrogen, argon, helium was developed. The technique provides the continuous control of gaseous mixture composition

  5. High Reynolds number flows using liquid and gaseous helium

    International Nuclear Information System (INIS)

    Donnelly, R.J.

    1991-01-01

    Consideration is given to liquid and gaseous helium as test fluids, high Reynolds number test requirements in low speed aerodynamics, the measurement of subsonic flow around an appended body of revolution at cryogenic conditions in the NTF, water tunnels, flow visualization, the six component magnetic suspension system for wind tunnel testing, and recent aerodynamic measurements with magnetic suspension systems. Attention is also given to application of a flow visualization technique to a superflow experiment, experimental investigations of He II flows at high Reynolds numbers, a study of homogeneous turbulence in superfluid helium, and thermal convection in liquid helium

  6. Kinetics of gaseous uranium hexafluoride reaction with hydrogen chloride

    International Nuclear Information System (INIS)

    Ezubchenko, A.N.; Ilyukhin, A.I.; Merzlyakov, A.V.

    1993-01-01

    Kinetics of decrease of concentration of gaseous uranium hexafluoride in reaction with hydrogen chloride at temperatures close to room ones, was investigated by the method of IR spectroscopy. It was established that the process represented the first order reaction by both UF 6 and HCl. Activation energy of the reaction was determined: 7.6 ± 0.7 kcal/mol. Specific feature of reaction kinetics was noted: inversely proportional dependence of effective constant on UF 6 initial pressure. 5 refs., 3 figs

  7. Gaseous waste deposition preventive device for glass melting furnace

    International Nuclear Information System (INIS)

    Takano, Sueo

    1998-01-01

    The device of the present invention comprises a heater for heating pressurized air and a moisturizer for mixing steams with the pressurized air heated by the heater to make moisturized pressurized air. Steams are mixed to rise humidity by the moisturizing up to the saturated vapor pressure at the temperature of the heating by heating pressurized air as an object of moisturizing by the heater to prevent dew condensation while increasing the amount of steams to be mixed. With such procedures, moisture enriched pressurized air can be jetted out thereby enabling to prevent deposition of solid materials and crystallized materials of gaseous wastes. (T.M.)

  8. Fundamental laws of separation by the gaseous diffusion process

    International Nuclear Information System (INIS)

    Bouligand, G.M.

    1964-01-01

    Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [fr

  9. Ionization and scintillation of nuclear recoils in gaseous xenon

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

    2015-09-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  10. Innovative applications and developments of micro-pattern gaseous detectors

    CERN Document Server

    Francke, Tom

    2014-01-01

    Study of nature and the world around us has been a primary motivation for scientists and researchers for centuries. Advanced methods in the study of elementary particles have led to even greater discoveries in recent years. "Innovative Applications and Developments of Micro-Pattern Gaseous Detectors" focuses on the analysis and use of various gas detection systems, providing a detailed description of some of the most commonly used gas detectors and the science behind them. From early detectors to modern tools and techniques, this book will be of particular use to practitioners and researchers in chemical engineering and materials science, in addition to students and academicians concentrating in the field.

  11. Gaseous 83mKr generator for KATRIN

    Science.gov (United States)

    Sentkerestiová, J.; Dragoun, O.; Lebeda, O.; Ryšavý, M.; Sturm, M.; Vénos, D.

    2018-04-01

    Monoenergetic conversion electrons from the 83mKrKr isomeric state have been proven to be useful in the calibration of several tritium neutrino mass and dark matter experiments. In this paper the design and characteristics of the gaseous 83mKrKr generator, including the 83Rb/83mKrKr source behavior in tritium, for the KATRIN experiment are presented. Using Si(Li) and silicon drift detectors (SDD) detectors, the half-life of the 83mKrKr isomeric state was measured to be 1.8620 ± 0.0019 h.

  12. Reliability study: maintenance facilities Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Post, B.E.; Sikorski, P.A.; Fankell, R.; Johnson, O.; Ferryman, D.S.; Miller, R.L.; Gearhart, E.C.; Rafferty, M.J.

    1981-08-01

    A reliability study of the maintenance facilities at the Portsmouth Gaseous Diffusion Plant has been completed. The reliability study team analyzed test data and made visual inspections of each component contributing to the overall operation of the facilities. The impacts of facilities and equipment failures were given consideration with regard to personnel safety, protection of government property, health physics, and environmental control. This study revealed that the maintenance facilities are generally in good condition. After evaluating the physical condition and technology status of the major components, the study team made several basic recommendations. Implementation of the recommendations proposed in this report will help assure reliable maintenance of the plant through the year 2000

  13. Two-stroke engine with gaseous and liquid fuel injection

    Energy Technology Data Exchange (ETDEWEB)

    Laursen, Rene Sejer [MAN Diesel and Turbo SE, Copenhagen (Denmark)

    2012-08-15

    The need to lower emissions of CO{sub 2}, NO{sub x}, SO{sub x} and particulates as well as rising oil prices have increased engine operators' interest in alternative fuels and fuel flexibility. The low speed two-stroke ME-GI and ME-LGI dual-fuel engines with diesel pilot injection from MAN Diesel and Turbo offer the opportunity of utilising fuels such as LNG, LPG, and methanol in a wide range of liquid to gaseous fuel ratios. (orig.)

  14. The UK market for gaseous emissions control equipment

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-09-01

    The report analyses the changes in demand for gaseous emissions control equipment in the United Kingdom over the next 5 years. It discusses the factors affecting demand such as legislation reporting of environmental performance, and economic factors. It looks at environmental expenditure by UK industry. Markets are examined, for VOC abatement systems; thermal incinerators; adsorption equipment; catalytic oxidisers; absorption equipment; biological treatments; cryogenic equipment; SO{sub x} abatement equipment; wet FGD; wet dry FGD, dry scrubbers; NOx abatement systems; selective catalytic reduction; and selective non-catalytic reduction. Profiles are given of 16 leading suppliers.

  15. Buildup of 236U in the gaseous diffusion plant product

    International Nuclear Information System (INIS)

    Ford, J.S.

    1975-01-01

    A generalized projection of the average annual 236 U concentration that can be expected in future enriched uranium product from the US-ERDA gaseous diffusion plants when reprocessed fuels become available for cascade feeding is given. It is concluded that the buildup of 236 U is not an ever-increasing function, but approaches a limiting value. Projected concentrations result in only slight separative work losses and present no operational problem to ERDA in supplying light water reactor requirements. The use of recycle uranium from power reactor spent fuels will result in significant savings in natural uranium feed

  16. Radiation protection with consumer products containing gaseous tritium light sources

    International Nuclear Information System (INIS)

    Rahders, Erio; Haeusler, Uwe

    2017-01-01

    Consumer products containing gaseous tritium light sources (GTLS) were examined with respect to their radiological safety potential regarding leak tightness or accidents. The maximum tritium leakage rate of 2.7 Bq/d determined from experimental testing is well below the criterion for leak tightness of sealed radioactive sources in DIN 25426-4. In order to investigate the incorporation of tritium due to contact with consumer products, 2 scenarios were reviewed; the correct use of a tritium watch and the accident scenario with a keyring.

  17. Gaseous elemental mercury (GEM fluxes over canopy of two typical subtropical forests in south China

    Directory of Open Access Journals (Sweden)

    Q. Yu

    2018-01-01

    Full Text Available Mercury (Hg exchange between forests and the atmosphere plays an important role in global Hg cycling. The present estimate of global emission of Hg from natural source has large uncertainty, partly due to the lack of chronical and valid field data, particularly for terrestrial surfaces in China, the most important contributor to global atmospheric Hg. In this study, the micrometeorological method (MM was used to continuously observe gaseous elemental mercury (GEM fluxes over forest canopy at a mildly polluted site (Qianyanzhou, QYZ and a moderately polluted site (Huitong, HT, near a large Hg mine in subtropical south China for a full year from January to December in 2014. The GEM flux measurements over forest canopy in QYZ and HT showed net emission with annual average values of 6.67 and 0.30 ng m−2 h−1, respectively. Daily variations of GEM fluxes showed an increasing emission with the increasing air temperature and solar radiation in the daytime to a peak at 13:00, and decreasing emission thereafter, even as a GEM sink or balance at night. High temperature and low air Hg concentration resulted in the high Hg emission in summer. Low temperature in winter and Hg absorption by plant in spring resulted in low Hg emission, or even adsorption in the two seasons. GEM fluxes were positively correlated with air temperature, soil temperature, wind speed, and solar radiation, while it is negatively correlated with air humidity and atmospheric GEM concentration. The lower emission fluxes of GEM at the moderately polluted site (HT when compared with that in the mildly polluted site (QYZ may result from a much higher adsorption fluxes at night in spite of a similar or higher emission fluxes during daytime. This shows that the higher atmospheric GEM concentration at HT restricted the forest GEM emission. Great attention should be paid to forests as a crucial increasing Hg emission source with the decreasing atmospheric GEM concentration

  18. Atmospheric polycyclic aromatic hydrocarbons (PAHs) in Asia: A review from 1999 to 2004

    International Nuclear Information System (INIS)

    Chang, K.-F.; Fang, G.-C.; Chen, J.-C.; Wu, Y.-S.

    2006-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are present in both gaseous and particulate phases. These compounds are considered to be atmospheric contaminants and are human carcinogens. Many studies have monitored atmospheric particulate and gaseous phases of PAH in Asia over the past 5 years. This work compares and discusses different sample collection, pretreatment and analytical methods. The main PAH sources are traffic exhausts (AcPy, FL, Flu, PA, Pyr, CHR, BeP) and industrial emissions (BaP, BaA, PER, BeP, COR, CYC). PAH concentrations are highest in areas of traffic, followed by the urban sites, and lowest in rural sites. Meteorological conditions, such as temperature, wind speed and humidity, strongly affect PAH concentrations at all sampling sites. This work elucidates the characteristics, sources and distribution, and the healthy impacts of atmospheric PAH species in Asia. - This work summarizes the characteristics, sources and distribution, and the healthy impacts of atmospheric PAH species in Asia

  19. Gaseous elemental mercury in the marine boundary layer and air-sea flux in the Southern Ocean in austral summer.

    Science.gov (United States)

    Wang, Jiancheng; Xie, Zhouqing; Wang, Feiyue; Kang, Hui

    2017-12-15

    Gaseous elemental mercury (GEM) in the marine boundary layer (MBL), and dissolved gaseous mercury (DGM) in surface seawater of the Southern Ocean were measured in the austral summer from December 13, 2014 to February 1, 2015. GEM concentrations in the MBL ranged from 0.4 to 1.9ngm -3 (mean±standard deviation: 0.9±0.2ngm -3 ), whereas DGM concentrations in surface seawater ranged from 7.0 to 75.9pgL -1 (mean±standard deviation: 23.7±13.2pgL -1 ). The occasionally observed low GEM in the MBL suggested either the occurrence of atmospheric mercury depletion in summer, or the transport of GEM-depleted air from the Antarctic Plateau. Elevated GEM concentrations in the MBL and DGM concentrations in surface seawater were consistently observed in the ice-covered region of the Ross Sea implying the influence of the sea ice environment. Diminishing sea ice could cause more mercury evasion from the ocean to the air. Using the thin film gas exchange model, the air-sea fluxes of gaseous mercury in non-ice-covered area during the study period were estimated to range from 0.0 to 6.5ngm -2 h -1 with a mean value of 1.5±1.8ngm -2 h -1 , revealing GEM (re-)emission from the East Southern Ocean in summer. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Polybrominated diphenyl ethers in atmosphere and soil of a production area in China: levels and partitioning.

    Science.gov (United States)

    Jin, Jun; Wang, Ying; Liu, Weizhi; Yang, Congqiao; Hu, Jicheng; Cui, Jian

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) were measured in atmosphere and soil samples taken in winter and summer at a PBDE production area of Laizhou Bay in China. The concentrations of Sigma11PBDE were 0.017-1.17 ng/m3 in gaseous phase, 0.5-161.1 ng/m3 in particulate phase, and 73-2629 ng/g dry weight in soil samples. The PBDE congener pattern in the gaseous phase differed from that in the particulate phase, and the PBDE congener pattern in the particulate phase was similar with that in soil. This demonstrated that there was little difference with atmospheric particle-soil transfer efficiency among PBDE congeners. In addition, there were seasonal variations in percentages on particle for lower brominated congeners. The BDE-28 was mostly in the gaseous phase in summer (88.3%), whereas the average proportion of BDE-28 in gaseous phase in winter was 38.9%. Higher brominated congeners (i.e., BDE-206, BDE-207, BDE-208, and BDE-209) were bound to the atmospheric particulate phase, and their potentials for long-range migration were mainly affected by the environmental behavior of atmospheric particles. Results indicated that PBDE congeners in summer were closer to gas-particle partition equilibrium than in winter. Temperature should be considered the main factor causing nonequilibrium in winter.

  1. Polybrominated diphenyl ethers in atmosphere and soil of a production area in China: Levels and partitioning

    Institute of Scientific and Technical Information of China (English)

    Jun Jin; Ying Wang; Weizhi Liu; Congqiao Yang; Jicheng Hu; Jian Cui

    2011-01-01

    Polybrominated diphenyl ethers (PBDEs) were measured in atmosphere and soil samples taken in winter and summer at a PBDE production area of Laizhou Bay in China. The concentrations of ∑11 PBDE were 0.017-1.17 ng/m3 in gaseous phase, 0.5-161.1 ng/m3 in particulate phase, and 73-2629 ng/g dry weight in soil samples. The PBDE congener pattern in the gaseous phase differed from that in the particulate phase, and the PBDE congener pattern in the particulate phase was similar with that in soil. This demonstrated that there was little difference with atmospheric panicle-soil transfer efficiency among PBDE congeners. In addition, there were seasonal variations in percentages on particle for lower brominated congeners. The BDE-28 was mostly in the gaseous phase in summer (88.3%),whereas the average proportion of BDE-28 in gaseous phase in winter was 38.9%. Higher brominated congeners (i.e., BDE-206, BDE207, BDE-208, and BDE-209) were bound to the atmospheric particulate phase, and their potentials for long-range migration were mainly affected by the environmental behavior of atmospheric particles. Results indicated that PBDE congeners in summer were closer to gas-particle partition equilibrium than in winter. Temperature should be considered the main factor causing nonequilibrium in winter.

  2. Some aspects of numerical analysis of turbulent gaseous and spray combustion

    International Nuclear Information System (INIS)

    Takagi, T.

    1991-01-01

    In this paper numerical calculations and analysis on turbulent non-premixed gaseous and spray combustion are reviewed. Attentions were paid to the turbulent flow and combustion modeling applicable to predicting the flow, mixing and combustion of gaseous fuels and sprays. Some of the computed results of turbulent gaseous non-premixed (diffusion) flames with and without swirl and transient spray combustion were compared with experimental ones to understand the processes in the flame and to assure how the computations predict the experiments

  3. Safety aspects of the design of a PWR gaseous radwaste treatment system using hydrogen recombiners

    International Nuclear Information System (INIS)

    Glibert, R.; Nuyt, G.; Herin, S.; Fossion, P.

    1978-01-01

    PWR Gaseous radwaste treatment system is essential for the reduction of impact on environment of the nuclear power plants. Decay tank system has been used for the retention of the radioactive gaseous fission products generated in the primary coolant. The use of a system combining decay tanks and hydrogen recombiner units is described in this paper. Accent is put on the safety aspects of this gaseous radwaste treatment facilitystudied by BN for a Belgian Power Plant. (author)

  4. Dynamical behaviour of gaseous halo in a disk galaxy

    International Nuclear Information System (INIS)

    Ikeuchi, S.; Habe, A.

    1981-01-01

    Assuming that the gas in the halo of a disk galaxy is supplied from the disk as a hot gas, the authors have studied its dynamical and thermal behaviour by means of a time dependent, two-dimensional hydrodynamic code. They suppose the following boundary conditions at the disk. (i) The hot gas with the temperature Tsub(d) and the density nsub(d) is uniform at r=4-12 kpc in the disk and it is time independent. (ii) This hot gas rotates with the stellar disk in the same velocity. (iii) This hot gas can escape freely from the disk to the halo. These conditions will be verified if the filling factor of hot gas is so large as f=0.5-0.8, as proposed by McKee and Ostriker (1977). The gas motion in the halo has been studied for wider ranges of gas temperature and its density at the disk than previously studied. At the same time, the authors have clarified the observability of various types of gaseous haloes and discuss the roles of gaseous halo on the evolution of galaxies. (Auth.)

  5. Control of semivolatile radionuclides in gaseous effluents at nuclear facilities

    International Nuclear Information System (INIS)

    1982-01-01

    An up-to-date review is presented of the subject, combining the results of laboratory studies on control of the most important semivolatile radionuclides in gaseous effluents at nuclear facilities and the results of operating experience in that area. Ruthenium is the most significant semivolatile contaminant in gaseous effluents at nuclear facilities. Volatilization of ruthenium can be reduced by various means, in particular by adding reductants. Volatilized ruthenium can be retained by adsorbents such as silica gel and ferric-oxide-based materials. Decontamination factors in the order of 10 3 have been obtained with these adsorbents under optimum conditions. Volatilized ruthenium can also be removed by other equipment such as condensers and scrubbers. Experience with high-level liquid waste solidification plants has shown that, in general, ruthenium volatilization is in the order of 10% or more unless special treatment is undertaken. There is little experience with ruthenium adsorbers in plants. Silica gel seems to have performed best, with ruthenium decontamination factors of about 10 2 to 10 3 . However, feed-to-stack ruthenium decontamination factors of 10 9 or more have been obtained even without ruthenium adsorbers. Other semivolatiles are relatively insignificant under normal conditions because of a low level of volatilization potential or mass or activity in the inventory. Moreover, owing to particulate formation, they can be easily removed without specific equipment

  6. Liquefied Gaseous Fuels Spill Test Facility: Overview of STF capabilities

    International Nuclear Information System (INIS)

    Gray, H.E.

    1993-01-01

    The Liquefied Gaseous Fuels Spill Test Facility (STF) constructed at the Department of Energy's Nevada Test Site is a basic research tool for studying the dynamics of accidental releases of various hazardous liquids. This Facility is designed to (1) discharge, at a controlled rate, a measured volume of hazardous test liquid on a prepared surface of a dry lake bed (Frenchman Lake); (2) monitor and record process operating data, close-in and downwind meteorological data, and downwind gaseous concentration levels; and (3) provide a means to control and monitor these functions from a remote location. The STF will accommodate large and small-scale testing of hazardous test fluid release rates up to 28,000 gallons per minute. Spill volumes up to 52,800 gallons are achievable. Generic categories of fluids that can be tested are cryogenics, isothermals, aerosol-forming materials, and chemically reactive. The phenomena that can be studied include source definition, dispersion, and pool fire/vapor burning. Other capabilities available at the STF include large-scale wind tunnel testing, a small test cell for exposing personnel protective clothing, and an area for developing mitigation techniques

  7. Starlight excitation of permitted lines in gaseous nebulae

    International Nuclear Information System (INIS)

    Grandi, S.A.

    1975-01-01

    The weak heavy element permitted lines observed in the spectra of gaseous nebula have, with only a few exceptions, been thought to be excited only by recombination. The accuracy of this assumption for individual lines in nebula spectra is investigated in detail via model nebula calculations. First, approximations and techniques of calculation are considered for the three possible excitation mechanisms: recombination, resonance fluorescence by the starlight continuum, and resonance fluorescence by other nebular emission lines. Next, the permitted lines of O I as observed in gaseous nebulae are discussed. Thirdly, it is shown that varying combinations of recombination, resonance fluorescence by starlight, and resonance fluorescence by other nebula lines can successfully account for the observed strengths in the Orion Nebula of lines of the following ions: C II, N I, N II, N III, O II, Ne II, Si II, Si III, and S III. A similar analysis is performed for the lines in the spectra of the planetary nebulae NGC7662 and NGC7027, and, with some exceptions, satisfactory agreement between the observed and predicted line strengths is found. Finally, observations of the far red spectra of the Orion Nebula, the planetary nebulae NGC3242, NGC6210, NGC2392, IC3568, IC4997, NGC7027, and MGC7662, and the reflection nebulae IC431 and NGC2068 are reported

  8. Control of technetium at the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Saraceno, A.J.

    1981-01-01

    Technetium-99 entered the gaseous diffusion complex as a volatile impurity in recycled uranium that was fed to the Paducah Gaseous Diffusion Plant. Subsequently, it entered the Oak Ridge and Portsmouth cascades as an impurity in Paducah product feed. Most of the technetium was adsorbed on cascade equipment in increasingly high concentrations as it moved up the cascade. Since the low energy beta radiation produced by technetium cannot penetrate cascade equipment, it presents no significant hazard to workers as long as it remains inside of equipment. However, when equipment that contains high concentrations of technetium is opened for maintenance or change-out, precautions are taken to ensure worker safety. Traps containing activated alumina are used at the plant vent streams to limit radioactive emissions as far as possible. Annual vent stream emissions have been well below DOE limits. To allow continued compliance, other potential trapping agents have been tested. Several that limit emissions more effectively than activated alumina have been found. Other traps containing magnesium fluoride are used in the upper cascade to reduce the technetium concentration. Waste solutions from decontamination can also contain technetium. These solutions must either be stored for controlled discharge or treated to remove the technetium. To allow the latter, an ion exchange facility is being installed for operation by the end of FY-1982. Liquid discharges at Portsmouth have usually been less than 5% of the DOE imposed limits

  9. Development and prospects of the new gaseous detector 'Micromegas'

    International Nuclear Information System (INIS)

    Giomataris, Y.

    1998-01-01

    We report results obtained with the novel gaseous Micromegas detector (MICRO MEsh GAseous Structure), which is under development at Saclay. A simple theory to explain the advantage of the small amplification gap (50-100 μm) is developed. A set of large detectors was exposed during several months in high-intensity particle beams. Full efficiency and a large plateau has been obtained with a 3 mm conversion gap. With a conversion gap as small as 1 mm the efficiency reaches 96 %. A spatial resolution better then 60 μm has been observed with anode strips of 317 μm pitch. Simulations show that with a pitch of 100 μm and the appropriate gas an accuracy of 10 μm and a time resolution of 1 νs is within reach. This development leads to a new generation of cheap position sensitive detectors which would permit high precision tracking or vertexing close to the interaction region, in very high-rate environments. (author)

  10. The Effect of Gaseous Ozone in Infected Root Canal

    Science.gov (United States)

    Ajeti, Nova Nexhmije; Pustina-Krasniqi, Teuta; Apostolska, Sonja

    2018-01-01

    OBJECTIVES: During the treatment of chronic apical periodontitis and pulp necrosis the main role is to irrigate the root canal. AIM: The aim of this in vivo study was to irrigate with 0.9% NaCl (Natrium Chloride), 2.5 % NaOCl (Sodium Hypochlorite Solution, Sigma Aldrich - Germany) and 2% CHX (Chlorhexidine Digluconate Solution, Sigma Aldrich - Spain) combined with Gaseous Ozone (Prozone WH, Austria). MATERIAL AND METHODS: This study was realised in the University Dentistry Clinical Centre of Kosovo (UDCCK), respectively in the Department of Endodontic and Dental Pathology, Dental Branch, Faculty of Medicine, Prishtina, Kosovo. The 40 subjects involved in this study belonged to both genders, in age between 15 -65 years. The sample selection was randomised. The retroalveolar radiography for each patient was taken in the suspected tooth. As a therapeutic plan the authors decided to disinfect the root canal with the irrigants, as follows: 2.5 % NaOCl, 2 % CHX and gaseous ozone. RESULTS: The statistical analyses were based on Kruskal - Vallis test, X - test, DF = 3, r irrigants 0.9%, 2.5 % NaOCl and 2% CHX, it was concluded that the number of colonies of aerobic and anaerobic bacteria was reduced. PMID:29531611

  11. Solid-state photoelectrochemical H2 generation with gaseous reactants

    International Nuclear Information System (INIS)

    Iwu, Kingsley O.; Galeckas, Augustinas; Kuznetsov, Andrej Yu.; Norby, Truls

    2013-01-01

    Photocurrent and H 2 production were demonstrated in an all solid-state photoelectrochemical cell employing gaseous methanol and water vapour at the photoanode. Open circuit photovoltage of around −0.4 V and short circuit photocurrent of up to 250 μA/cm 2 were obtained. At positive bias, photocurrent generation was limited by the irradiance, i.e., the amount of photogenerated charge carriers at the anode. Time constants and impedance spectra showed an electrochemical capacitance of the cell of about 15 μF/cm 2 in the dark, which increased with increasing irradiance. With only water vapour at the anode, the short circuit photocurrent was about 6% of the value with gaseous methanol and water vapour. The photoanode and electrocatalyst on carbon paper support were affixed to the proton conducting membrane using Nafion ® as adhesive, an approach that yielded photocurrents up to 15 times better than that of a cell assembled by hot-pressing, in spite of the overall cell resistance of the latter being up to five times less than that of the former. This is attributed, at least partially, to reactants being more readily available at the photoanode of the better performing cell

  12. Trapping technology for gaseous fission products from voloxidation process

    International Nuclear Information System (INIS)

    Shin, Jin Myeong; Park, J. J.; Park, G. I.; Jung, I. H.; Lee, H. H.; Kim, G. H.; Yang, M. S.

    2005-05-01

    The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, 14 C, Kr, Xe, I and 3 H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and 14 C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene Copolymer) is also proposed as a conversion media to HTO for 3 H. This report will be used as a useful means for analyzing the known trapping technologies and help selecting the appropriate trapping methods for trapping volatile and semi-volatile fission products, long-lived fission products, and major heat sources generated from a voloxidation process. It can also be used to design an off-gas treatment system

  13. Trapping technology for gaseous fission products from voloxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jin Myeong; Park, J. J.; Park, G. I.; Jung, I. H.; Lee, H. H.; Kim, G. H.; Yang, M. S

    2005-05-15

    The objective of this report is to review the different technologies for trapping the gaseous wastes containing Cs, Ru, Tc, {sup 14}C, Kr, Xe, I and {sup 3}H from a voloxidation process. Based on literature reviews and KAERI's experimental results on the gaseous fission products trapping, appropriate trapping method for each fission product has been selected considering process reliability, simplicity, decontamination factor, availability, and disposal. Specifically, the most promising trapping method for each fission product has been proposed for the development of the INL off-gas trapping system. A fly ash filter is proposed as a trapping media for a cesium trapping unit. In addition, a calcium filter is proposed as a trapping media for ruthenium, technetium, and {sup 14}C trapping unit. In case of I trapping unit, AgX is proposed. For Kr and Xe, adsorption on solid is proposed. SDBC (Styrene Divinyl Benzene Copolymer) is also proposed as a conversion media to HTO for {sup 3}H. This report will be used as a useful means for analyzing the known trapping technologies and help selecting the appropriate trapping methods for trapping volatile and semi-volatile fission products, long-lived fission products, and major heat sources generated from a voloxidation process. It can also be used to design an off-gas treatment system.

  14. Mevva ion source operated in purely gaseous mode

    International Nuclear Information System (INIS)

    Yushkov, G.Y.; MacGill, R.A.; Brown, I. G.

    2003-01-01

    We have operated a vacuum arc ion source in such a way as to form beams of purely gaseous ions. The vacuum arc configuration that is conventionally used to produce intense beams of metal ions was altered so as to form gaseous ion beams, with only minimal changes to the external circuitry and no changes at all internally to the ion source. In our experiments we formed beams from oxygen (O + and O 2 + ), nitrogen (N + and N 2 + ), argon (Ar + ) and carbon dioxide (C + , CO 2 + , O + and O 2 + ) at extraction voltage of 2 to 50 kV. We used a pulsed mode of operation, with beam pulses approximately 50 milliseconds long and repetition rate 10 pulses per second, for a duty cycle of about 50%. Downstream ion beam current as measured by a 5 cm diameter Faraday cup was typically 0.5 mA pulse or about 250 (micro)A time averaged. This time averaged beam current is very similar to that obtained for metal ions when the source is operated in the usual vacuum arc mode. Here we describe the modifications made to the source and the results of our investigations

  15. Atmospheric pollution in the mediterranean area: geochemical studies of aerosols and rain waters

    International Nuclear Information System (INIS)

    Caboi, R.; Chester, R.

    1998-01-01

    It is now recognised that the atmosphere is a major pathway for the transport of material to the oceans. The material in the atmosphere is present as gaseous and particulate (aerosol) phases. Aerosols may be removed from the atmosphere by a combination of 'dry' (i.e. not involving an atmospheric aqueous phase) and 'wet' (precipitation scavenging) processes. Thus, aerosols are intimately related to rain waters, and interactions between the two are discusses below in relation to the input of material to the Mediterranean Sea

  16. Review of microfluidic cell culture devices for the control of gaseous microenvironments in vitro

    Science.gov (United States)

    Wu, H.-M.; Lee, T.-A.; Ko, P.-L.; Chiang, H.-J.; Peng, C.-C.; Tung, Y.-C.

    2018-04-01

    Gaseous microenvironments play important roles in various biological activities in vivo. However, it is challenging to precisely control gaseous microenvironments in vitro for cell culture due to the high diffusivity nature of gases. In recent years, microfluidics has paved the way for the development of new types of cell culture devices capable of manipulating cellular microenvironments, and provides a powerful tool for in vitro cell studies. This paper reviews recent developments of microfluidic cell culture devices for the control of gaseous microenvironments, and discusses the advantages and limitations of current devices. We conclude with suggestions for the future development of microfluidic cell culture devices for the control of gaseous microenvironments.

  17. Diffusional limits to the consumption of atmospheric methane by soils

    Science.gov (United States)

    Striegl, Robert G.

    1993-01-01

    Net transport of atmospheric gases into and out of soil systems is primarily controlled by diffusion along gas partial pressure gradients. Gas fluxes between soil and the atmosphere can therefore be estimated by a generalization of the equation for ordinary gaseous diffusion in porous unsaturated media. Consumption of CH4 by methylotrophic bacteria in the top several centimeters of soil causes the uptake of atmospheric CH4 by aerated soils. The capacity of the methylotrophs to consume CH4 commonly exceeds the potential of CH4 to diffuse from the atmosphere to the consumers. The maximum rate of uptake of atmospheric CH4 by soil is, therefore, limited by diffusion and can be calculated from soil physical properties and the CH4 concentration gradient. The CH4 concentration versus depth profile is theoretically described by the equation for gaseous diffusion with homogeneous chemical reaction in porous unsaturated media. This allows for calculation of the in situ rate of CH4 consumption within specified depth intervals.

  18. Determination and analysis of uptake of gaseous hydrogen peroxide by red spruce seedlings, determined by CSTR-type chamber experiments

    International Nuclear Information System (INIS)

    Claiborn, C.S.; Aneja, V.P.; Carbonell, R.G.

    1991-01-01

    In order to better understand the pathways for damage, the fate of gaseous hydrogen peroxide in red spruce needles was examined. The uptake of gaseous hydrogen peroxide by red spruce trees was determined from controlled exposure chamber experiments in which the chamber behaved as a Continuous Stirred Tank Reactor (CSTR). The results from these experiments were analyzed using a detailed transport model developed from fundamental principles, in order to determine the fate of hydrogen peroxide in the needles and characterize the exposure. The chamber was specially designed to accommodate highly reactive gases. All inner surfaces were Teflon-coated to minimize wall losses. Fluxes of hydrogen peroxide, carbon dioxide, and water vapor were determined. Both daytime and nighttime conditions were examined. Although other investigators have reported that the flux of other, less water-soluble pollutants to red spruce decreases at night when the stomata closes, the hydrogen peroxide flux did not exhibit this behavior. The results of these studies suggest that, at the concentrations observed in the atmosphere, hydrogen peroxide does not reach the inner, mesophyll tissues, but is lost in water condensing in the cuticular wax residing in the stomatal antechamber, above the stomata. The implications of the condensation in the stomatal antechamber and subsequent reactions occurring in this water for forest damage are discussed

  19. Stomatal clustering in Begonia associates with the kinetics of leaf gaseous exchange and influences water use efficiency.

    Science.gov (United States)

    Papanatsiou, Maria; Amtmann, Anna; Blatt, Michael R

    2017-04-01

    Stomata are microscopic pores formed by specialized cells in the leaf epidermis and permit gaseous exchange between the interior of the leaf and the atmosphere. Stomata in most plants are separated by at least one epidermal pavement cell and, individually, overlay a single substomatal cavity within the leaf. This spacing is thought to enhance stomatal function. Yet, there are several genera naturally exhibiting stomata in clusters and therefore deviating from the one-cell spacing rule with multiple stomata overlaying a single substomatal cavity. We made use of two Begonia species to investigate whether clustering of stomata alters guard cell dynamics and gas exchange under different light and dark treatments. Begonia plebeja, which forms stomatal clusters, exhibited enhanced kinetics of stomatal conductance and CO2 assimilation upon light stimuli that in turn were translated into greater water use efficiency. Our findings emphasize the importance of spacing in stomatal clusters for gaseous exchange and plant performance under environmentally limited conditions. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  20. Dispersion of effluents in the atmosphere; Dispersion des effluents dans l`atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-12-31

    This conference day was organized by the `convection` section of the French association of thermal engineers with the support of the environment and energy mastery agency (ADEME). This book of proceedings contains 10 papers entitled: `physical modeling of atmospheric dispersion in wind tunnels. Some industrial examples`; `modeling of the noxious effects of a fire on the environment of an industrial site: importance of thermal engineering related hypotheses`; `atmospheric diffusion of a noxious cloud: fast evaluation method of safety areas around refrigerating installations that use ammonia`; `modeling of atmospheric flows in urban areas in order to study the dispersion of pollutants`; `use of a dispersion parameter to characterize the evolution of a diffusion process downstream of a linear source of passive contaminant placed inside a turbulent boundary layer`; `elements of reflexion around the development of an analytical methodology applied to the elaboration of measurement strategies of air quality in ambient and outdoor atmospheres around industrial sites`; `state-of-the-art about treatment techniques for VOC-rich gaseous effluents`; `characteristics of the time variation of the atmospheric pollution in the Paris region and visualization of its space distribution`; `mass-spectrometry for the measurement of atmospheric pollutants`; `volume variations in natural convection turbulence`. (J.S.)

  1. Dispersion of effluents in the atmosphere; Dispersion des effluents dans l`atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This conference day was organized by the `convection` section of the French association of thermal engineers with the support of the environment and energy mastery agency (ADEME). This book of proceedings contains 10 papers entitled: `physical modeling of atmospheric dispersion in wind tunnels. Some industrial examples`; `modeling of the noxious effects of a fire on the environment of an industrial site: importance of thermal engineering related hypotheses`; `atmospheric diffusion of a noxious cloud: fast evaluation method of safety areas around refrigerating installations that use ammonia`; `modeling of atmospheric flows in urban areas in order to study the dispersion of pollutants`; `use of a dispersion parameter to characterize the evolution of a diffusion process downstream of a linear source of passive contaminant placed inside a turbulent boundary layer`; `elements of reflexion around the development of an analytical methodology applied to the elaboration of measurement strategies of air quality in ambient and outdoor atmospheres around industrial sites`; `state-of-the-art about treatment techniques for VOC-rich gaseous effluents`; `characteristics of the time variation of the atmospheric pollution in the Paris region and visualization of its space distribution`; `mass-spectrometry for the measurement of atmospheric pollutants`; `volume variations in natural convection turbulence`. (J.S.)

  2. Analysis of gaseous-phase stable and radioactive isotopes in the unsaturated zone, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Yang, I.C.; Haas, H.H.; Weeks, E.P.; Thorstenson, D.C.

    1985-01-01

    The Nevada Nuclear Waste Storage Investigations Project of the US Department of Energy provides that agency with data for evaluating volcanic tuff beneath Yucca Mountain, Nevada, to determine its suitability for a potential repository of high-level radioactive waste. Thickness of the unsaturated zone, which consists of fractured, welded and nonwelded tuff, is about 1640 to 2460 feet (500 to 750 meters). One question to be resolved is an estimate of minimum ground-water traveltime from the disturbed zone of the potentail repository to the accessible environment. Another issue is the potential for diffusive or convective gaseous transport of radionuclides from an underground facility in the unsaturated zone to the accessible environment. Gas samples were collected at intervals to a depth of 1200 feet from the unsaturated zone at Yucca Mountain, Nevada. Samples were analyzed for major atmospheric gases; carbon dioxide in the samples was analyzed for carbon-14 activity and for delta 13 C; water vapor in the samples was analyzed for deuterium and oxygen-18. These data could provide insight into the nature of unsaturated zone transport processes. 15 refs., 4 figs., 4 tabs

  3. Factors influencing concentrations of dissolved gaseous mercury (DGM) and total mercury (TM) in an artificial reservoir

    International Nuclear Information System (INIS)

    Ahn, Myung-Chan; Kim, Bomchul; Holsen, Thomas M.; Yi, Seung-Muk; Han, Young-Ji

    2010-01-01

    The effects of various factors including turbidity, pH, DOC, temperature, and solar radiation on the concentrations of total mercury (TM) and dissolved gaseous mercury (DGM) were investigated in an artificial reservoir in Korea. Episodic total mercury accumulation events occurred during the rainy season as turbidity increased, indicating that the TM concentration was not controlled by direct atmospheric deposition. The DGM concentration in surface water ranged from 3.6 to 160 pg/L, having a maximum in summer and minimum in winter. While in most previous studies DGM was controlled primarily by a photo-reduction process, DGM concentrations tracked the amount of solar radiation only in winter when the water temperature was fairly low in this study. During the other seasons microbial transformation seemed to play an important role in reducing Hg(II) to Hg(0). DGM increased as dissolved organic carbon (DOC) concentration increased (p-value < 0.01) while it increased with a decrease of pH (p-value < 0.01). - Long-term in-situ monitoring of TM and DGM concentrations with various factors was executed in a large artificial reservoir in this study.

  4. Evaluation of the population dose due to the gaseous emission of a radioisotopes production unit

    International Nuclear Information System (INIS)

    Gordon, A.M.P.L.; Jacomino, V.M.F.; Sordi, G.-M.A.A.

    1990-05-01

    In order to control the emission of gaseous radioactive iodine from the unit responsible for the production of radioisotopes of IPEN-CNEN/SP, a discharge monitoring is carried out. In 1988 an activity of 65 GBq of I-131 was discharged to the environment. Based upon this value and the site analysis, the effective equivalent dose in the general public was evaluated for normal operation and for an incidental discharge. The evaluation was carried out by using a diffusion atmospheric model, 500 to 7000 m away from the discharge point and using 8 different wind direction sectors. The critical group was identified as being the people who lives 3000 m far from the discharge point, in the diffusion sector NW. The dose evaluated at this point is 10 9 times lower than the annual dose limit for individual of the public, according to Radiological Protection Standards. The derived limit for discharge of iodine was also evaluated and it was concluded that the IPEN-CNEN/SP can increase their production up to a level which results in an annual discharge of 1,5 x 10 12 of I-131. (author) [pt

  5. An improved microstrip plasma for optical emission spectrometry of gaseous species

    Energy Technology Data Exchange (ETDEWEB)

    Schermer, Susanne; Bings, Nicolas H.; Bilgic, Attila M.; Stonies, Robert; Voges, Edgar; Broekaert, Jose A.C. E-mail: jose.broekaert@chemie.uni-hamburg.de

    2003-09-26

    A modified compact 2.45 GHz microstrip plasma (MSP) operated with Ar as working gas at atmospheric pressure has been characterized and examined for its suitability for the determination of Hg as gaseous species by optical emission spectrometry. As a formerly described MSP the new device is provided on a sapphire substrate. The areas of plasma stability in terms of gas flow rates and microwave power for both MSPs with respect to plasma form and reflected power were investigated. Power levels of 5-40 W and Ar flow rates of 15-60 l/h were used. The modified MSP, which extends out of the channel in the sapphire substrate, was used for the recording of emission spectra for Hg vapor at different working conditions. Using optimized parameters a detection limit for Hg of less than 10 ng Hg/l Ar is obtained. The attainable excitation temperatures in the modified MSP at different microwave power were determined under the use of Fe as thermometric species and introducing ferrocene into the plasma. They were found to be at the order of 6000-7000 K for a power of 10-40 W and a gas flow of 15 l/h. It was shown that the modified MSP source can be combined with both a conventional monochromator with photomultiplier detection and a miniaturized spectrometer with CCD detection, whereby space-angle limitations are not stringent.

  6. Purification of free hydrogen or hydrogen combined in a gaseous mixture by chemical reactions with uranium

    International Nuclear Information System (INIS)

    Caron-Charles, M.; Gilot, B.

    1989-01-01

    Within the framework of the European fusion program, the authors are dealing with the tritium technology aspect. Hydrogen, free or under a combined form within a H 2 , N 2 , NH 3 , O 2 , gaseous mixture, can be purified by chemical reactions with uranium metal. The resulting reactions consist in absorbing the impurities without holding back H 2 . Working conditions have been defined according to two main goals: the formation of stable solid products, especially under hydrogenated atmosphere and the optimization of the material quantities to be used. Thermodynamical considerations have shown that the 950-1300 K temperature range should be suitable for this chemical process. Experiments performed with massive uranium set in a closed reactor at 973 K, have produced hydrogen according to the predicted reactions rates. But they have also pointed out the importance of interferences that might occur in the uranium-gas system, on the gases conversion rates. The comparison between the chemical kinetic ratings of the reactions of pure gases and the chemical kinetic ratings of the reactions of the same gases in mixture, has been set up. It proves that simultaneous reactions can modify the working conditions of the solid products formation, and particularly modify their structure. In this case, chemical kinetic ratings are increased up to their maximal value; that means surface phenomena are favoured as with uranium powder gases reactions. (orig.)

  7. Gaseous elemental mercury (GEM emissions from snow surfaces in northern New York.

    Directory of Open Access Journals (Sweden)

    J Alexander Maxwell

    Full Text Available Snow surface-to-air exchange of gaseous elemental mercury (GEM was measured using a modified Teflon fluorinated ethylene propylene (FEP dynamic flux chamber (DFC in a remote, open site in Potsdam, New York. Sampling was conducted during the winter months of 2011. The inlet and outlet of the DFC were coupled with a Tekran Model 2537A mercury (Hg vapor analyzer using a Tekran Model 1110 two port synchronized sampler. The surface GEM flux ranged from -4.47 ng m(-2 hr(-1 to 9.89 ng m(-2 hr(-1. For most sample periods, daytime GEM flux was strongly correlated with solar radiation. The average nighttime GEM flux was slightly negative and was not well correlated with any of the measured meteorological variables. Preliminary, empirical models were developed to estimate GEM emissions from snow surfaces in northern New York. These models suggest that most, if not all, of the Hg deposited with and to snow is reemitted to the atmosphere.

  8. Gaseous elemental mercury (GEM) emissions from snow surfaces in northern New York.

    Science.gov (United States)

    Maxwell, J Alexander; Holsen, Thomas M; Mondal, Sumona

    2013-01-01

    Snow surface-to-air exchange of gaseous elemental mercury (GEM) was measured using a modified Teflon fluorinated ethylene propylene (FEP) dynamic flux chamber (DFC) in a remote, open site in Potsdam, New York. Sampling was conducted during the winter months of 2011. The inlet and outlet of the DFC were coupled with a Tekran Model 2537A mercury (Hg) vapor analyzer using a Tekran Model 1110 two port synchronized sampler. The surface GEM flux ranged from -4.47 ng m(-2) hr(-1) to 9.89 ng m(-2) hr(-1). For most sample periods, daytime GEM flux was strongly correlated with solar radiation. The average nighttime GEM flux was slightly negative and was not well correlated with any of the measured meteorological variables. Preliminary, empirical models were developed to estimate GEM emissions from snow surfaces in northern New York. These models suggest that most, if not all, of the Hg deposited with and to snow is reemitted to the atmosphere.

  9. UV spectra and OH-oxidation kinetics of gaseous phase morpholinic compounds

    KAUST Repository

    Rachidi, Mariam El

    2014-05-01

    This paper presents an experimental study of the UV spectra as well as the kinetics of gaseous phase OH-oxidation of morpholine, N-formylmorpholine (NFM) and N-acetlymorpholine (NAM). The spectra recorded using a UV spectrometer in the spectral range 200-280nm show that the analytes mainly absorb at wavelengths less than 280nm. This indicates that their photolysis potential in the troposphere is insignificant. Meanwhile, the OH-reactivity of these analytes was studied using a triple-jacket 2m long reactor equipped with a multi-reflection system and coupled to an FTIR spectrometer. The experiments were carried out at 295 and 313K for the amine and amides, respectively. The study was conducted in the relative mode using isoprene and benzaldehyde as reference compounds. The rate constants obtained are 14.0±1.9, 4.0±1.1 and 3.8±1.0 (in units of 10-11cm3molecule-1s-1) for morpholine, NFM and NAM respectively. These results are discussed in terms of reactivity and compared to those obtained for other oxy-nitrogenated species. In addition, the determined rate constants are used to estimate effective atmospheric lifetimes of the investigated morpholinic compounds with respect to reaction with OH radicals. © 2014 Elsevier Ltd.

  10. UV spectra and OH-oxidation kinetics of gaseous phase morpholinic compounds

    KAUST Repository

    Rachidi, Mariam El; El Masri, A.; Roth, E.; Chakir, A.

    2014-01-01

    This paper presents an experimental study of the UV spectra as well as the kinetics of gaseous phase OH-oxidation of morpholine, N-formylmorpholine (NFM) and N-acetlymorpholine (NAM). The spectra recorded using a UV spectrometer in the spectral range 200-280nm show that the analytes mainly absorb at wavelengths less than 280nm. This indicates that their photolysis potential in the troposphere is insignificant. Meanwhile, the OH-reactivity of these analytes was studied using a triple-jacket 2m long reactor equipped with a multi-reflection system and coupled to an FTIR spectrometer. The experiments were carried out at 295 and 313K for the amine and amides, respectively. The study was conducted in the relative mode using isoprene and benzaldehyde as reference compounds. The rate constants obtained are 14.0±1.9, 4.0±1.1 and 3.8±1.0 (in units of 10-11cm3molecule-1s-1) for morpholine, NFM and NAM respectively. These results are discussed in terms of reactivity and compared to those obtained for other oxy-nitrogenated species. In addition, the determined rate constants are used to estimate effective atmospheric lifetimes of the investigated morpholinic compounds with respect to reaction with OH radicals. © 2014 Elsevier Ltd.

  11. WATER FORMATION IN THE UPPER ATMOSPHERE OF THE EARLY EARTH

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Benjamin; Carrasco, Nathalie; Marcq, Emmanuel; Vettier, Ludovic; Määttänen, Anni, E-mail: benjamin.fleury@latmos.ipsl.fr [Université Versailles St-Quentin, Sorbonne Universités, UPMC Univ. Paris 06, CNRS/INSU, LATMOS-IPSL, 11 Boulevard d’Alembert, F-78280 Guyancourt (France)

    2015-07-10

    The water concentration and distribution in the early Earth's atmosphere are important parameters that contribute to the chemistry and the radiative budget of the atmosphere. If the atmosphere above the troposphere is generally considered as dry, photochemistry is known to be responsible for the production of numerous minor species. Here we used an experimental setup to study the production of water in conditions simulating the chemistry above the troposphere of the early Earth with an atmospheric composition based on three major molecules: N{sub 2}, CO{sub 2}, and H{sub 2}. The formation of gaseous products was monitored using infrared spectroscopy. Water was found as the major product, with approximately 10% of the gas products detected. This important water formation is discussed in the context of the early Earth.

  12. Decomposition Characteristics of Benzene, Toluene and Xylene in an Atmospheric Pressure DC Corona Discharge II. Characteristics of Deposited By-products and Decomposition Process

    OpenAIRE

    SAKAI, Seiji; TAKAHASHI, Kazuhiro; SATOH, Kohki; ITOH, Hidenori

    2016-01-01

    Gaseous by-products and deposited material obtained from the decomposition of benzene, toluene and xylene in an atmospheric pressure DC corona discharge were minutely investigated by gas chromatograph mass spectrometry and infrared absorption spectroscopy, and the decomposition processes of benzene, toluene and xylene were estimated. It was found that carbon dioxide (CO2), carbon monoxide (CO), formic acid (HCOOH) and formic anhydride ((CHO)2) were the major gaseous by-products from benzene, ...

  13. High temperature behaviour of copper and silver in presence of gaseous carbon and of chlorine-water vapor mixtures

    International Nuclear Information System (INIS)

    Beloucif, Luisa

    1986-01-01

    This research thesis reports the study of the effects of gaseous chlorine, in various conditions, on two metals, copper and silver, the chlorides of which can be precisely characterized and dosed by using different methods. After an overview of different aspects of corrosion of metals by halogens, and of copper and silver behaviour in chloride environment, the author reports and discusses results of tests performed in dry chlorine at high temperature, and the establishment of temperature-pressure semi-thermodynamic diagrams. The next part reports and discusses tests performed in a controlled atmosphere in presence of humidity. For all these tests, the author notably comments and discusses the nature of formed products, sample aspect, reaction progress, and influence of temperature or humidity

  14. Hazardous gas treatment using atmospheric pressure microwave discharges

    International Nuclear Information System (INIS)

    Mizeraczyk, Jerzy; Jasinski, Mariusz; Zakrzewski, Zenon

    2005-01-01

    Atmospheric pressure microwave discharge methods and devices used for producing non-thermal plasmas for control of gaseous pollutants are described in this paper. The main part of the paper is concerned with microwave torch discharges (MTDs). Results of laboratory experiments on plasma abatement of several volatile organic compounds (VOCs) in their mixtures with either synthetic air or nitrogen in low (∼100 W) and moderate (200-400 W) microwave torch plasmas at atmospheric pressure are presented. Three types of MTD generators, i.e. low-power coaxial-line-based MTDs, moderate-power waveguide-based coaxial-line MTDs and moderate-power waveguide-based MTDs were used. The gas flow rate and microwave (2.45 GHz) power delivered to the discharge were in the range of 1-3 litre min -1 and 100-400 W, respectively. The concentrations of the processed gaseous pollutants were from several to several tens of per cent. The results showed that the MTD plasmas fully decomposed the VOCs at a relatively low energy cost. The energy efficiency of decomposition of several gaseous pollutants reached 1000 g (kW-h) -1 . This suggests that MTD plasmas can be useful tools for decomposition of highly concentrated VOCs

  15. Measurement of the Portsmouth Gaseous Diffusion Plant criticality accident alarm

    International Nuclear Information System (INIS)

    Tayloe, R.W. Jr.; McGinnis, B.

    1990-01-01

    Measurements of the Portsmouth Gaseous Diffusion Plant's nuclear criticality accident radiation alarm signal response time, sound wave frequency, and sound volume levels were made to demonstrate compliance with ANSI/ANS-8.3-1986. A steady-state alarm signal is produced within one-half second of obtaining a two-out-of-three detector trip. The fundamental alarm sound wave frequency is 440 hertz. The sound volume levels are greater than 10 decibels above background and ranged from 100 to 125 A-weighted decibels. The requirements of the standard were met; however the recommended maximum sound volume level of 115 dBA was exceeded. Emergency procedures require immediate evacuation upon initiation of a facility's radiation alarm. Comparison with standards for allowable time of exposure at different noise levels indicate that the elevated noise level at this location does not represent an occupational injury hazard. 8 refs., 5 figs

  16. Gaseous Tritium Light Sources in armament and watches industries

    International Nuclear Information System (INIS)

    Amme, Marcus; Siegenthaler, Roger

    2015-01-01

    The industrial application of Tritium gas enclosed in glass tubes is a modern way illuminating instruments and items wherever instant and independent readability is prerequisite. The GTLS (Gaseous Tritium Light Sources) technology follows the principle of radiation-induced luminescence and supersedes the luminous radioactive paints and their hazards such as particles erasure or heavy isotope use. Enclosure of tritium in glass is a demanding micro technology process and work needs to be performed in controlled areas due to handling of open sources. The storage and transport of the Tritium is done via licensed B(U)-containers coming from heavy water reactor sites, and disposal of radioactive Tritium wastes has to be compliant with national and international regulations for transport and waste management.

  17. Fluid simulation of beryllium transport in the ITER gaseous divertor

    International Nuclear Information System (INIS)

    Knoll, D.A.; Campbell, R.B.; McHugh, P.R.

    1994-01-01

    The transport of either intrinsic or injected impurities will play a crucial role in the energy loss mechanisms in the ITER gaseous/cold plasma target divertor. Both 1-D and 2-D multi-charge state fluid codes are used to model the transport of beryllium in the ITER SOL. Our major conclusion is that in order to model the containment of impurities, the background flow field must be known in detail. Comparing 1-D and 2-D solutions, hydrogen flow reversal plays an important role in the entrainment process. Further, the flow of particles from the core plasma also has a strong impact on the resultant entrainment of the impurities in both 1-D and 2-D. It is imperative that those components of poloidal velocity due to E x B and diamagnetic drifts be included in the models. (orig.)

  18. Gaseous diffusion plant transition from DOE to external regulation

    International Nuclear Information System (INIS)

    Dann, R.K.; Crites, T.R.; Rahm-Crites, L.K.

    1997-01-01

    After many years of operation as government-owned/contractor-operated facilities, large portions of the gaseous diffusion plants (GDPs) at Portsmouth, Ohio, and Paducah, Kentucky, were leased to the United States Enrichment Corporation (USEC). These facilities are now certified by the U.S. Nuclear Regulatory Commission (NRC) and subject to oversight by the Occupational Safety and Health Administration (OSHA). The transition from DOE to NRC regulation was more difficult than expected. The original commitment was to achieve NRC certification in October 1995; however, considerably more time was required and transition-related costs escalated. The Oak Ridge Operations Office originally estimated the cost of transition at $60 million; $240 million has been spent to date. The DOE's experience in transitioning the GDPs to USEC operation with NRC oversight provides valuable lessons (both positive and negative) that could be applied to future transitions

  19. The infrared spectrum of gaseous malonaldehyde (3-hydroxy-2-propenal)

    Science.gov (United States)

    Smith, Zuzana; Wilson, E. Bright; Duerst, Richard W.

    The infrared spectra of gaseous malonaldehyde and four of its deutero isotopes were recorded in the regions 4000-75 and 4000-400 cm -1, respectively. The vibrational fundamental frequencies were assigned in terms of C s molecular symmetry, primarily on the basis of transferring frequencies for similar modes and force constants from acrolein and other related molecules, plus the Redlich—Teller and reduced Redlich—Teller product rules. This assignment I does not agree well with a priori calculations of the frequencies received from two groups. Assignment II involved some changes in the intermediate frequency range which led to much better agreement with a priori values, but a conclusive choice has not been made.

  20. Angular resolution of the gaseous micro-pixel detector Gossip

    Science.gov (United States)

    Bilevych, Y.; Blanco Carballo, V.; van Dijk, M.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

    2011-06-01

    Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

  1. Angular resolution of the gaseous micro-pixel detector Gossip

    Energy Technology Data Exchange (ETDEWEB)

    Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S. [Nikhef, P.O. Box 41882, 1009 DB Amsterdam (Netherlands); Rogers, M. [Radboud University, P.O. Box 9102, 6500HC Nijmegen (Netherlands); Romaniouk, A.; Veenhof, R. [CERN, CH-1211, Geneve 23 (Switzerland)

    2011-06-15

    Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO{sub 2} 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

  2. Angular resolution of the gaseous micro-pixel detector Gossip

    International Nuclear Information System (INIS)

    Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

    2011-01-01

    Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

  3. Emulation workbench for position sensitive gaseous scintillation detectors

    International Nuclear Information System (INIS)

    Pereira, L.; Margato, L.M.S.; Morozov, A.; Solovov, V.; Fraga, F. A. F.

    2015-01-01

    Position sensitive detectors based on gaseous scintillation proportional counters with Anger-type readout are being used in several research areas such as neutron detection, search for dark matter and neutrinoless double beta decay. Design and optimization of such detectors are complex and time consuming tasks. Simulations, while being a powerful tool, strongly depend on the light transfer models and demand accurate knowledge of many parameters, which are often not available. Here we describe an alternative approach based on the experimental evaluation of a detector using an isotropic point-like light source with precisely controllable light emission properties, installed on a 3D positioning system. The results obtained with the developed setup at validation conditions, when the scattered light is strongly suppressed show good agreement with simulations

  4. Portsmouth Gaseous Diffusion Plant annual site environmental report for 1993

    Energy Technology Data Exchange (ETDEWEB)

    Horak, C.M. [ed.

    1994-11-01

    This calendar year (CY) 1993 annual report on environmental monitoring of the US Department of Energy`s (DOE`s) Portsmouth Gaseous Diffusion Plant (Portsmouth) and its environs consists of three separate documents: a summary pamphlet for the general public; a more detail discussion and of compliance status, data, and environmental impacts (this document); and a volume of detailed data that is available on request. The objectives of this report are to report compliance status during 1993; provide information about the plant site and plant operations; report 1993 monitoring data for the installation and its environs that may have been affected by operations on the plant site; document information on input and assumptions used in calculations; provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on quality assurance for the environmental monitoring program.

  5. Portsmouth Gaseous Diffusion Plant environmental report for 1992

    International Nuclear Information System (INIS)

    Horak, C.M.

    1993-09-01

    This calendar year (CY) 1992 annual report on environmental surveillance of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: narrative, summaries, and conclusions (Part 1) and data presentation (Part 2). The objectives of this report are to: (1) report 1992 monitoring data for the installation and its environs that may have been affected by operations on the plant site, (2) provide reasonably detailed information about the plant site and plant operations, (3) provide detailed information on input and assumptions used in all calculations, (4) provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and (5) provide general information on plant quality assurance

  6. Rapid monitoring of gaseous radionuclides using a portable spectrometer

    International Nuclear Information System (INIS)

    Chung, C.; Tsai, C.H.

    1995-01-01

    A field gamma ray spectrometer, consisting of a portable high purity germanium detector, portable multichannel analyser, and a notebook computer, was used to conduct in situ rapid scanning of radioactive Ar, Kr and Xe isotopes in the air around a nuclear facility. The portable gamma ray spectrometer was calibrated using Ar, Kr, and Xe radioisotopes, activated in a research reactor and released in a sealed chamber. The unit was further tested inside the reactor containment to monitor the concentration of 41 Ar. In a typical one hour field measurement, the detection limits for some rare gas radionuclides corresponded to dose rates around 0.1 nSv.h -1 , which is far less than the dose rate induced by derived air concentrations imposed by the authority. The dose rate due to ground level concentrations of gaseous radionuclides dispersed from a source, such a nuclear facility or nuclear test, can be monitored in a short period using the portable unit. (Author)

  7. Analysis of radiation fields in tomography on diffusion gaseous sound

    International Nuclear Information System (INIS)

    Bekman, I.N.

    1999-01-01

    Perspectives of application of equilibrium and stationary variants of diffusion tomography with radioactive gaseous sounds for spatial reconstruction of heterogeneous media in materials technology were considered. The basic attention were allocated to creation of simple algorithms of detection of sound accumulation on the background of monotonically varying concentration field. Algorithms of transformation of two-dimensional radiation field in three-dimensional distribution of radiation sources were suggested. The methods of analytical elongation of concentration field permitting separation of regional anomalies on the background of local ones and vice verse were discussed. It was shown that both equilibrium and stationary variants of diffusion tomography detect the heterogeneity of testing material, provide reduction of spatial distribution of elements of its structure and give an estimation of relative degree of defectiveness

  8. Persufflation (gaseous oxygen perfusion) as a method of heart preservation.

    Science.gov (United States)

    Suszynski, Thomas M; Rizzari, Michael D; Scott, William E; Eckman, Peter M; Fonger, James D; John, Ranjit; Chronos, Nicolas; Tempelman, Linda A; Sutherland, David E R; Papas, Klearchos K

    2013-04-22

    Persufflation (PSF; gaseous oxygen perfusion) is an organ preservation technique with a potential for use in donor heart preservation. Improved heart preservation with PSF may improve outcomes by maintaining cardiac tissue quality in the setting of longer cold ischemia times and possibly increasing the number of donor hearts available for allotransplant. Published data suggests that PSF is able to extend the cold storage times for porcine hearts up to 14 hours without compromising viability and function, and has been shown to resuscitate porcine hearts following donation after cardiac death. This review summarizes key published work on heart PSF, including prospective implications and future directions for PSF in heart transplantation. We emphasize the potential impact of extending preservation times and expanding donor selection criteria in heart allotransplant. Additionally, the key issues that need to be addressed before PSF were to become a widely utilized preservation strategy prior to clinical heart transplantation are summarized and discussed.

  9. Portsmouth Gaseous Diffusion Plant annual site environmental report for 1993

    International Nuclear Information System (INIS)

    Horak, C.M.

    1994-11-01

    This calendar year (CY) 1993 annual report on environmental monitoring of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (Portsmouth) and its environs consists of three separate documents: a summary pamphlet for the general public; a more detail discussion and of compliance status, data, and environmental impacts (this document); and a volume of detailed data that is available on request. The objectives of this report are to report compliance status during 1993; provide information about the plant site and plant operations; report 1993 monitoring data for the installation and its environs that may have been affected by operations on the plant site; document information on input and assumptions used in calculations; provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on quality assurance for the environmental monitoring program

  10. Wire gaseous coordinate detectors and their applications in biomedical research

    International Nuclear Information System (INIS)

    Peshekhonov, V.D.

    1986-01-01

    Wire gaseous coordinate detectors continue to be a basic tool in experimental high-energy physics and are being intensively introduced into related areas of science and technology, particularly biomedical research. The constant evolution of these detectors allows broad application of their new modificatons: multistep chambers, low-pressure detectors, time-projection chambers, and so on, so that detector systems are enriched with new possibilities. In this review we give the operating principles and fundamental parameters of these detectors and discuss some examples of how they are used in experimental physics. We also explore some of the features of the use of these detectors for research in molecular biology and medical diagnostics for examples of existing and projected setups

  11. A portable gas recirculation unit for gaseous detectors

    Science.gov (United States)

    Guida, R.; Mandelli, B.

    2017-10-01

    The use of greenhouse gases (usually C2H2F4, CF4 and SF6) is sometimes necessary to achieve the required performance for some gaseous detectors. The consumption of these gases in the LHC systems is reduced by recycling the gas mixture thanks to a complex gas recirculation system. Beyond greenhouse gas consumption due to LHC systems, a considerable contribution is generated by setups used for LHC detector upgrade projects, R&D activities, detector quality assurance or longevity tests. In order to minimise this emission, a new flexible and portable gas recirculation unit has been developed. Thanks to its low price, flexibility and user-friendly operation it can be easily adapted for the different types of detector systems and set-ups.

  12. Ps beam production and scattering from gaseous targets

    International Nuclear Information System (INIS)

    Garner, A.J.; Laricchia, G.; Oezen, A.

    1996-01-01

    We have investigated the conversion of a positron beam into an ortho-Ps beam via charge exchange in gaseous H 2 , He and Ar at energies up to 120 eV and gas pressures up to 14 μmHg. H 2 has been found to be the most efficient converter at energies up to 90 eV. At higher energies, Ar has been found to be the best. Total cross sections of ortho-Ps scattering from H 2 and He have also been measured. A comparison with available theories suggests that electron exchange at lower energies and target inelastic collisions at higher energies are playing a major role in the collisions. (author)

  13. Radioactive diffusion gaseous probe technique for study adsorbent structure inhomogeneity

    International Nuclear Information System (INIS)

    Zyuzin, A.Yu.; Korobkov, V.I.; Bekman, I.N.

    1990-01-01

    One of the versions of the method of diffusion gaseous probe - method of longitudinal shear in combination with autoradiography (ARG) - was used for characterising sorbents and catalysts, which are considered to be promising for reprocessing of sulfur-containing natural gases. Hydrogen sulfide, labelled with 35 S was used as diffusion radioactive probe. Zeolite granules of 4A type and granulated adsorbents on the basis of CR and AM aluminium oxides, which are industrial catalysts of Clauss reaction developed at SNEA company, were used as objects under investigation. It is shown that technique for fabrication of 4A zeolite granules leads to asymmetrical pore distribution over the granule diameter. Technique for AM granule fabrication leads to occuRrence of local inhomogeneities of the structure in the form of narrow coaxial rings with decreased or increased local adsorption ability. Granules of adsorbent of CR type are characterized by rather homogeneous structure. It is recommended to use the mentioned method for industrial adsorbent diagnosis

  14. A novel fast timing micropattern gaseous detector: FTM

    CERN Document Server

    De Oliveira, Rui; Sharma, Archana

    2015-01-01

    In recent years important progress in micropattern gaseous detectors has been achieved in the use of resistive material to build compact spark-protected devices. The novel idea presented here consists of the polarisation of WELL structures using only resistive coating. This allows a new device to be built with an architecture based on a stack of several coupled layers where drift and WELL multiplication stages alternate in the structure. The signals from each multiplication stage can be read out from any external readout boards through the capacitive couplings. Each layer provides a signal with a gain of 10^4-10^5. The main advantage of this new device is the dramatic improvement of the timing provided by the competition of the ionisation processes in the different drift regions, which can be exploited for fast timing at the high luminosity accelerators (e.g. HL-LHC upgrade) as well as far applications like medical imaging.

  15. A novel fast timing micropattern gaseous detector: FTM

    CERN Document Server

    De Oliveira, Rui; Maggi, Marcello

    2015-01-01

    In recent years important progress in micropattern gaseous detectors has been achieved in the use of resistive material to build compact spark-protected devices. The novel idea presented here consists of the polarisation of WELL structures using only resistive electrodes. This allows a new device to be built with an architecture based on a stack of several coupled layers where drift and WELL multiplication stages alternate in the structure. The signals from each multiplication stage can be read out from any external readout boards through the capacitive couplings. Each layer provides a signal with a gain of 10^4 - 10^5. The main advantage of this new device is the dramatic improvement of the timing provided by the competition of the ionisation processes in the different drift regions, which can be exploited for fast timing at the high luminosity accelerators (e.g. HL-LHC upgrade) as well as applications outside particle physics.

  16. Thermodynamic cycle calculations for a pumped gaseous core fission reactor

    International Nuclear Information System (INIS)

    Kuijper, J.C.; Van Dam, H.

    1991-01-01

    Finite and 'infinitesimal' thermodynamic cycle calculations have been performed for a 'solid piston' model of a pumped Gaseous Core Fission Reactor with dissociating reactor gas, consisting of Uranium, Carbon and Fluorine ('UCF'). In the finite cycle calculations the influence has been investigated of several parameters on the thermodynamics of the system, especially on the attainable direct (nuclear to electrical) energy conversion efficiency. In order to facilitate the investigation of the influence of dissociation, a model gas, 'Modelium', was developed, which approximates, in a simplified, analytical way, the dissociation behaviour of the 'real' reactor gas. Comparison of the finite cycle calculation results with those of a so-called infinitesimal Otto cycle calculation leads to the conclusion that the conversion efficiency of a finite cycle can be predicted, without actually performing the finite cycle calculation, with reasonable accuracy, from the so-called 'infinitesimal efficiency factor', which is determined only by the thermodynamic properties of the reactor gas used. (author)

  17. Second Generation Gaseous Biofuels: from Biomass to Gas Grid

    International Nuclear Information System (INIS)

    Guerrini, O.; Perrin, M.; Marchand, B.; Prieur-Vernat, A.

    2013-01-01

    Gaseous biofuels and biomethane production by thermochemical pathway has many assets and, already, it should be seen as an essential component of future French and European energy panorama by 2020. As a biomass gasification process is used, a very wide range of biomass is accessible, guaranteeing a significant development potential of the sector. Because of the inherent advantages of the methanation reaction, methanation processes have very high overall energy efficiency, today comparable to other technologies for energy recovery from biomass. Moreover, these can be further enhanced by a waste heat valorization. The existence of technology adapted to installations of medium size (20-80 MW biomethane) promotes strong integration in the local area and is exemplary in a framework of sustainable development. Most of the steps of the process of biomethane production from biomass are at present commercially available. However, the technical feasibility of the whole production line of biomethane was not demonstrated to an industrial scale yet. (authors)

  18. Behaviour of gaseous alkali compounds from coal gasification

    International Nuclear Information System (INIS)

    Nykaenen, J.

    1996-01-01

    In this project the behaviour of alkali compounds has been studied with a chemical equilibrium model. The goal is to evaluate the possibilities to remove the sodium and potassium compounds together with the fly ash particles by using a ceramic honeycomb filter. The studied processes include both CO 2 /O 2 - and air-blown gasification and combustion. The results show that the difference between the processes with flue gas recirculation and air-blown processes is small. This is due to that the equilibrium concentration of the dominant gaseous alkali compound, chloride, is more or less the same in both processes. This research project is closely connected to the EU-project coordinated by the Delft University of Technology (DUT). In that project alkali concentration of the fuel gas from a 1.6 MW pilot plant will be measured. During the next phase of this research the results from DUT will be compared with the results of this presentation. (author)

  19. Electron Drift Properties in High Pressure Gaseous Xenon

    Energy Technology Data Exchange (ETDEWEB)

    Simón, A.; et al.

    2018-04-05

    Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White is a High Pressure Xenon gas TPC with electroluminescent amplification, a 1:2 scale model of the future NEXT-100 detector, which will be dedicated to neutrinoless double beta decay searches. NEXT-White has been operating at Canfranc Underground Laboratory (LSC) since December 2016. The drift parameters have been measured using $^{83m}$Kr for a range of reduced drift fields at two different pressure regimes, namely 7.2 bar and 9.1 bar. The results have been compared with Magboltz simulations. Agreement at the 5% level or better has been found for drift velocity, longitudinal diffusion and transverse diffusion.

  20. Quantitative Thermochemical Measurements in High-Pressure Gaseous Combustion

    Science.gov (United States)

    Kojima, Jun J.; Fischer, David G.

    2012-01-01

    We present our strategic experiment and thermochemical analyses on combustion flow using a subframe burst gating (SBG) Raman spectroscopy. This unconventional laser diagnostic technique has promising ability to enhance accuracy of the quantitative scalar measurements in a point-wise single-shot fashion. In the presentation, we briefly describe an experimental methodology that generates transferable calibration standard for the routine implementation of the diagnostics in hydrocarbon flames. The diagnostic technology was applied to simultaneous measurements of temperature and chemical species in a swirl-stabilized turbulent flame with gaseous methane fuel at elevated pressure (17 atm). Statistical analyses of the space-/time-resolved thermochemical data provide insights into the nature of the mixing process and it impact on the subsequent combustion process in the model combustor.

  1. Portsmouth Gaseous Diffusion Plant Environmental report for 1990

    Energy Technology Data Exchange (ETDEWEB)

    Counce-Brown, D. (ed.)

    1991-09-01

    This calendar year 1990 annual report on environmental surveillance of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: the summary, discussion, and conclusions (Part 1) and the data presentation (Part 2). The objectives of this report are as follows: report 1990 monitoring data for the installation and its environs that may have been affected by operations on the plant site, provide reasonably detailed information about the plant site and plant operations, provide detailed information on input and assumptions used in all calculations, provide trend analyses (when appropriate) to indicate increases and decreases in environmental impact, and provide general information on plant quality assurance.

  2. Mechanical effects of gaseous detonations on a flexible confinement

    International Nuclear Information System (INIS)

    Brossard, J.; Renard, J.

    1981-01-01

    A mathematical model was developed for evaluating the effect of a detonating gaseous mixture on its elastic circular confinement. The data provided by the model were compared with experimental results. The confinement materials investigated include polyvinylchloride and stainless steel. Measurements of transverse and longitudinal deformations of the confinement material at several detonation velocities and for different material properties made it possible to determine the deformation characteristics, taking into account the precursor effect, the oscillations and their frequencies, the deformation ratio, and the dynamic amplifying factors. A certain lack of agreement between the theoretical data obtained with the aid of the model and the experimental results is probably related to simplified assumptions made in the model regarding the pressure distributions and a failure to take into account viscosity effects

  3. Paducah Gaseous Diffusion Plant environmental report for 1989

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.W. (ed.) (Martin Marietta Energy Systems, Inc., Oak Ridge, TN (USA))

    1990-10-01

    This two-part environmental report is published annually. It reflects the results of a comprehensive, year-round program to monitor the impact of operations at Paducah Gaseous Diffusion Plant (PGDP) on the area's groundwater and surface waters, soil, air quality, vegetation, and wildlife. In addition, an assessment of the effect of PGDP effluents on the resident human population is made. PGDP's overall goal for environmental management is to protect the environment and PGDP's neighbors and to maintain full compliance with all current regulations. The current environmental strategy is to identify any deficiencies and to develop a system to resolve them. The long-range goal of environmental management is to minimize the source of pollutants, to reduce the formation of waste, and to minimize hazardous waste by substitution of materials. 36 refs.

  4. Dry deposition of gaseous radioiodine and particulate radiocaesium onto leafy vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Tschiersch, Jochen, E-mail: tschiersch@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Shinonaga, Taeko [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg (Germany); Heuberger, Heidi [TU Muenchen, Center of Life and Food Sciences Weihenstephan, Duernast 2, 85350 Freising (Germany)

    2009-10-15

    Radionuclides released to the atmosphere during dry weather (e.g. after a nuclear accident) may contaminate vegetable foods and cause exposure to humans via the food chain. To obtain experimental data for an appropriate assessment of this exposure path, dry deposition of radionuclides to leafy vegetables was studied under homogeneous and controlled greenhouse conditions. Gaseous {sup 131}I-tracer in predominant elemental form and particulate {sup 134}Cs-tracer at about 1 {mu}m diameter were used to identify susceptible vegetable species with regard to contamination by these radionuclides. The persistence was examined by washing the harvested product with water. The vegetables tested were spinach (Spinacia oleracea), butterhead lettuce (Lactuca sativa var. capitata), endive (Cichorium endivia), leaf lettuce (Lactuca sativa var. crispa), curly kale (Brassica oleracea convar. acephala) and white cabbage (Brassica oleracea convar. capitata). The variation of radionuclides deposited onto each vegetable was evaluated statistically using the non-parametric Kruskal-Wallis Test and the U-test of Mann-Whitney. Significant differences in deposited {sup 131}I and {sup 134}Cs activity concentration were found among the vegetable species. For {sup 131}I, the deposition velocity to spinach normalized to the biomass of the vegetation was 0.5-0.9 cm{sup 3} g{sup -1} s{sup -1} which was the highest among all species. The particulate {sup 134}Cs deposition velocity of 0.09 cm{sup 3} g{sup -1} s{sup -1} was the highest for curly kale, which has rough and structured leaves. The lowest deposition velocity was onto white cabbage: 0.02 cm{sup 3} g{sup -1} s{sup -1} (iodine) and 0.003 cm{sup 3} g{sup -1} s{sup -1} (caesium). For all species, the gaseous iodine deposition was significantly higher compared to the particulate caesium deposition. The deposition depends on the sensitive parameters leaf area, stomatal aperture, and plant morphology. Decontamination by washing with water was very

  5. Acid-base thermochemistry of gaseous aliphatic α-aminoacids.

    Science.gov (United States)

    Bouchoux, Guy; Huang, Sihua; Inda, Bhawani Singh

    2011-01-14

    Acid-base thermochemistry of isolated aliphatic amino acids (denoted AAA): glycine, alanine, valine, leucine, isoleucine and proline has been examined theoretically by quantum chemical computations at the G3MP2B3 level. Conformational analysis on neutral, protonated and deprotonated species has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. Comparison of the G3MP2B3 theoretical proton affinities, PA, and ΔH(acid) with experimental results is shown to be correct if experimental thermochemistry is re-evaluated and adapted to the most recent acidity-basicity scales. From this point of view, a set of evaluated proton affinities of 887, 902, 915, 916, 919 and 941 kJ mol(-1), and a set of evaluated ΔH(acid) of 1433, 1430, 1423, 1423, 1422 and 1426 kJ mol(-1), is proposed for glycine, alanine, valine, leucine, isoleucine and proline, respectively. Correlations with structural parameters (Taft's σ(α) polarizability parameter and molecular size) suggest that polarizability of the side chain is the major origin of the increase in PA and decrease in ΔH(acid) along the homologous series glycine, alanine, valine and leucine/isoleucine. Heats of formation of gaseous species AAA, AAAH(+) and [AAA-H](-) were computed at the G3MP2B3 level. The present study provides previously unavailable Δ(f)H°(298) for the ionized species AAAH(+) and [AAA-H](-). Comparison with Benson's estimate, and correlation with molecular size, show that several experimental Δ(f)H°(298) values of neutral or gaseous AAA might be erroneous.

  6. Analytical and numerical study of a gaseous plasma dipole in the UHF frequency band

    NARCIS (Netherlands)

    Melazzi, Davide; Lancellotti, Vito; Capobianco, Antonio Daniele

    2017-01-01

    Gaseous plasma antennas are appealing in applications in which reconfigurability is desired, because the radiation properties can be changed by tuning the plasma parameters. In this paper, an analytical and numerical analysis of a gaseous plasma dipole that works in the 0.3-3 GHz frequency range is

  7. EQUILIBRIUM AND KINETIC NITROGEN AND OXYGEN-ISOTOPE FRACTIONATIONS BETWEEN DISSOLVED AND GASEOUS N2O

    NARCIS (Netherlands)

    INOUE, HY; MOOK, WG

    1994-01-01

    Experiments were performed to determine the equilibrium as well as kinetic stable nitrogen and oxygen isotope fractionations between aqueous dissolved and gaseous N2O. The equilibrium fractionations, defined as the ratio of the isotopic abundance ratios (15R and 18R, respectively) of gaseous and

  8. Gaseous polycyclic aromatic hydrocarbon concentrations are higher in urban forests than adjacent open areas during summer but not in winter – Exploratory study

    International Nuclear Information System (INIS)

    Viippola, Viljami; Rantalainen, Anna-Lea; Yli-Pelkonen, Vesa; Tervo, Peatta; Setälä, Heikki

    2016-01-01

    While the potential of plants to uptake polycyclic aromatic hydrocarbons (PAHs) is widely acknowledged, empirical evidence of the effects of this process on local atmospheric PAH concentrations and human health is tenuous. We measured gaseous PAH concentrations using passive samplers in urban tree-covered areas and adjacent open, treeless areas in a near-road environment in Finland to gain information on the ability of urban vegetation to improve air quality. The ability of urban, mostly deciduous, vegetation to affect PAHs was season dependent: during summer, concentrations were significantly higher in tree-covered areas, while in the fall, concentrations in open areas exceeded those in tree-covered areas. During winter, concentrations in tree-covered areas were either lower or did not differ from those in open areas. Results of this study imply that the commonly believed notion that trees unequivocally improve air quality does not apply to PAHs studied here. - Highlights: • Urban tree-cover increases gaseous PAH concentrations during summertime. • Elevated PAH concentrations do not clearly correspond with vegetation properties. • Tree-cover attenuates seasonal PAH concentration fluctuation. - Higher ambient gaseous PAH concentrations were detected within urban tree cover as compared to open areas during summertime.

  9. Passive sampling for the isotopic fingerprinting of atmospheric mercury

    Science.gov (United States)

    Bergquist, B. A.; MacLagan, D.; Spoznar, N.; Kaplan, R.; Chandan, P.; Stupple, G.; Zimmerman, L.; Wania, F.; Mitchell, C. P. J.; Steffen, A.; Monaci, F.; Derry, L. A.

    2017-12-01

    Recent studies show that there are variations in the mercury (Hg) isotopic signature of atmospheric Hg, which demonstrates the potential for source tracing and improved understanding of atmospheric cycling of Hg. However, current methods for both measuring atmospheric Hg and collecting enough atmospheric Hg for isotopic analyses require expensive instruments that need power and expertise. Additionally, methods for collecting enough atmospheric Hg for isotopic analysis require pumping air through traps for long periods (weeks and longer). Combining a new passive atmospheric sampler for mercury (Hg) with novel Hg isotopic analyses will allow for the application of stable Hg isotopes to atmospheric studies of Hg. Our group has been testing a new passive sampler for gaseous Hg that relies on the diffusion of Hg through a diffusive barrier and adsorption onto a sulphur-impregnated activated carbon sorbent. The benefit of this passive sampler is that it is low cost, requires no power, and collects gaseous Hg for up to one year with linear, well-defined uptake, which allows for reproducible and accurate measurements of atmospheric gaseous Hg concentrations ( 8% uncertainty). As little as one month of sampling is often adequate to collect sufficient Hg for isotopic analysis at typical background concentrations. Experiments comparing the isotopic Hg signature in activated carbon samples using different approaches (i.e. by passive diffusion, by passive diffusion through diffusive barriers of different thickness, by active pumping) and at different temperatures confirm that the sampling process itself does not impose mass-independent fractionation (MIF). However, sampling does result in a consistent and thus correctable mass-dependent fractionation (MDF) effect. Therefore, the sampler preserves Hg MIF with very high accuracy and precision, which is necessary for atmospheric source tracing, and reasonable MDF can be estimated with some increase in error. In addition to

  10. Rancho Seco building wake effects on atmospheric diffusion

    International Nuclear Information System (INIS)

    Start, G.E.; Cate, J.H.; Dickson, C.R.; Ricks, N.R.; Ackerman, G.R.; Sagendorf, J.F.

    1977-11-01

    A series of 23 paired gaseous tracer releases at the Rancho Seco Nuclear Power Station in 1975 was the third of several tests designed to investigate the diffusion characteristics of the atmosphere under conditions of low windspeed and temperature inversion. This test also evaluated the effects of flow around buildings upon dilution of pollutants. Gaseous tracers were laterally dispersed about six times more than the expected amounts from Pasquill--Gifford curves of sigma-y. Most of this increase could be related to observed variance of the horizontal wind direction (meandering). For ground-level releases the effective sigma-z values were 16 times greater than the corresponding values from the Pasquill--Gifford curves. Measured ground-level axial concentrations were about 75 times smaller than predicted by the Gaussian diffusion equation for a ground-level release when Pasquill--Gifford values of sigma-y and sigma-z were used

  11. Spectroradiometric inspection of nuclear pollution in the atmosphere based on photochemical effects

    Science.gov (United States)

    Chistyakova, Liliya K.; Kopytin, Yurii D.

    2005-07-01

    Results of theoretical and experimental investigations of remote monitoring methods based on secondary radioactivity effects including anomalous gaseous fields and their emissions in optical and microwave ranges are discussed. The feasibility of remote registration of secondary emission and absorption spectra from weakly ionized regions in the atmosphere above nuclear power engineering objects, dumps, and tailings dumps of nuclear wastes are examined. Based on the literature data on the excess concentrations of aerosol and gaseous components produced in radiation fields above their background levels, the diffusion parameters of radioactive emissions in the atmosphere are evaluated. The methods under consideration are shown to be promising for ecological monitoring of atmospheric radioactive pollution. High sensitivities of these methods enable pollutants to be detected at long distances. Simultaneous use of passive and active methods gives additional information on the parameters of radioactive pollution.

  12. Development of atmosphere-soil-vegetation model for investigation of radioactive materials transport in terrestrial biosphere

    International Nuclear Information System (INIS)

    Katata, Genki; Nagai, Haruyasu; Zhang, Leiming; Held, Andreas; Serca, Dominique; Klemm, Otto

    2010-01-01

    In order to investigate the transport of radionuclides in the terrestrial biosphere we have developed a one-dimensional numerical model named SOLVEG that predicts the transfer of water, heat, and gaseous and particulate matters in atmosphere-soil-vegetation system. The SOLVEG represents atmosphere, soil, and vegetation as an aggregation of several layers. Basic equations used in the model are solved using the finite difference method. Most of predicted variables are interrelated with the source/sink terms of momentum, water, heat, gases, and particles based on mathematically described biophysical processes in atmosphere, soil and vegetation. The SOLVEG can estimate dry, wet and fog deposition of gaseous and particulate matters at each canopy layer. Performance tests of the SOLVEG with several observational sites were carried out. The SOLVEG predicted the observed temporal changes in water vapor, CO 2 , and ozone fluxes over vegetated surfaces. The SOLVEG also reproduced measured fluxes of fog droplets and of fine aerosols over the forest. (author)

  13. Potential Trace Metal–Organic Complexation in the Atmosphere

    Directory of Open Access Journals (Sweden)

    Hiroshi Okochi

    2002-01-01

    Full Text Available It is possible that metal–organic complexation enhances the uptake of gaseous organic compounds and the solubility of metals in aerosols and atmospheric water. We investigated potential atmospheric organic ligands and the enhanced uptake of hydroxy-, oxo-, and dicarboxylic acids as well as dicarbonyls into atmospheric aqueous aerosol. We examined complexation with transition metals (iron, manganese, nickel, copper, zinc and lead on the basis of available references and our experimental data. Humic-like substances are most likely ligands in the atmosphere, although this is a poorly characterized material. A number of polycarboxylic acids and hydroxy forms (e.g., citric and tartronic acids effectively complex metals such as copper in atmospheric aerosols. The simple equilibrium model calculations show that the effect of the complexation on the gas–aqueous phase partition of gaseous atmospheric ligands is quite small for the ligands with the high physical Henry’s law constants, e.g., dicarboxylic acids represented by oxalic acid, even if they have high affinity with metal ions. The lower Henry’s law constants of the α-dicarbonyls, such as glyoxal and methylglyoxal, mean that the complexation could lead to profound increases in their partition into the aqueous phase. Despite quantum mechanical arguments for copper–glyoxal complexes, experiments showed no evidence of complexation between either hydrated or unhydrated α-dicarbonyls and the cupric ion. By contrast the β-dicarbonyl, malondialdehyde, has properties that would allow it to partition into atmospheric water via the complexation with metal ions under some conditions.

  14. In Situ Gaseous Reduction Pilot Demonstration - Final Report

    International Nuclear Information System (INIS)

    Thornton, E.C.; Phelan, J.M.; Giblin, J.T.; Olsen, K.B.; Miller, R.D.; Gilmore, T.J.

    1999-01-01

    The demonstration of the IGRS approach conducted at SWMU 143 on the White Sands Missile Range has provided information needed to complete a technical performance assessment and cost analysis of the technology. At least 70% of the Cr(VI) present in contaminated sediment at the site was reduced, thus verifying the effectiveness of the approach. Most of the treatment occurred in a zone located from approximately4 to 10 ft below ground surface, which appears to be a higher permeability interval. A deeper zone from approximately10 to 16 ft that contains lower levels of contamination was essentially unaffected. The deeper zone is somewhat finer grained and has a higher clay content and is, thus, less permeable. It appears that most of the treatment gas was channeled through the higher, more-permeable zone and the lower zone was bypassed. Treatment of the lower zone could probably be accomplished, however, if a second injection well were installed and screened across the zone so that treatment gas could be forced into this interval. The amount of H 2 S consumed during the test exceeded the amount predicted by the laboratory treatability study. In addition, the levels of H 2 S observed at the extraction wells were relatively low, even though a significant level of treatment was observed at the site. It is inferred that interfering reactions or slower reaction kinetics are the likely source of consumption of extra H 2 S observed in the field. Future laboratory work will be undertaken to investigate the nature of these chemical reactions and the reaction rates associated with the gaseous reduction of Cr(VI) in soils. Elucidation of these effects may reveal methods for improving the effectiveness of the technology and reducing unit costs. A life-cycle cost model was developed for the technology based on demonstration information (Hogan 1998). This model suggests that the technology should compare favorably with excavation from a cost basis for larger sites, especially when

  15. In Situ Gaseous Reduction Pilot Demonstration - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, E.C.; Phelan, J.M.; Giblin, J.T.; Olsen, K.B.; Miller, R.D.; Gilmore, T.J.

    1999-02-23

    The demonstration of the IGRS approach conducted at SWMU 143 on the White Sands Missile Range has provided information needed to complete a technical performance assessment and cost analysis of the technology. At least 70% of the Cr(VI) present in contaminated sediment at the site was reduced, thus verifying the effectiveness of the approach. Most of the treatment occurred in a zone located from {approximately}4 to 10 ft below ground surface, which appears to be a higher permeability interval. A deeper zone from {approximately}10 to 16 ft that contains lower levels of contamination was essentially unaffected. The deeper zone is somewhat finer grained and has a higher clay content and is, thus, less permeable. It appears that most of the treatment gas was channeled through the higher, more-permeable zone and the lower zone was bypassed. Treatment of the lower zone could probably be accomplished, however, if a second injection well were installed and screened across the zone so that treatment gas could be forced into this interval. The amount of H{sub 2}S consumed during the test exceeded the amount predicted by the laboratory treatability study. In addition, the levels of H{sub 2}S observed at the extraction wells were relatively low, even though a significant level of treatment was observed at the site. It is inferred that interfering reactions or slower reaction kinetics are the likely source of consumption of extra H{sub 2}S observed in the field. Future laboratory work will be undertaken to investigate the nature of these chemical reactions and the reaction rates associated with the gaseous reduction of Cr(VI) in soils. Elucidation of these effects may reveal methods for improving the effectiveness of the technology and reducing unit costs. A life-cycle cost model was developed for the technology based on demonstration information (Hogan 1998). This model suggests that the technology should compare favorably with excavation from a cost basis for larger sites

  16. Liquid and gaseous wastes from pressurised water reactors: International comparison

    International Nuclear Information System (INIS)

    Benedittini, M.

    1989-04-01

    This report presents the main results of a comparison on radioactive effluents releases from ninety-four PWRs in the following countries: Belgium, Federal Republic of Germany, France, Japan, Sweden, Switzerland and the United States. For liquid releases, distinctions have been undertaken between tritium and no tritium activities and for gaseous releases between noble gases and halogens-aerosols. Data have been collected from literature published or by contacting utilities responsible or authorities in order to constitute a data bank. However for the comparison, reactors for which commercial operation starts before July 1974, have been excluded. As far as the main comparative results are concerned, the averages of tritium activity per energy production unit for liquid releases are ranging between 1840 GBq/TWh and 3000 GBq/TWh and two groups of countries may be noted: those for which the results are around 2000 GBq/TWh as Frg, Japan and Switzerland and those which have an activity level around 3000 GBq/TWh as Belgium, France and Sweden. The United States are between these two groups. A factor which may provide an explanation for these discrepancies concerns practices for primary circuit: recycling it, leads to a lower tritium activity for releases and to a higher tritium activity concentration in the primary circuit. Excluding tritium, mean liquid activities per reactor are widely varying from one country to another: - lower than 0,05 GBq in Japan and in Switzerland; - from one thousand to two thousand times higher in France, Sweden and the United States. Discrepancies for gaseous activities are narrower: a factor of 40 in noble gases activities and a factor of 25 for halogens and aerosols activities. In conclusion, for activities of the tritium liquid as well as activities of all other types of radionuclides, countries can be shared in two groups according the activity level - For the lowest: FRG, Japan and Switzerland; - For the highest: Belgium, France and Sweden

  17. Liquid and gaseous wastes from pressurised water reactors: international comparison

    International Nuclear Information System (INIS)

    Benedittini, M.

    1989-04-01

    This report presents the main results of a comparison on radioactive effluents releases from ninety-four PWRs in the following countries: Belgium, Federal Republic of Germany, France, Japan, Sweden, Switzerland and the United States. For liquid releases, distinctions have been undertaken between tritium and no tritium activities and for gaseous releases between noble gases and halogens-aerosols. Data have been collected from literature published or by contacting utilities responsible or authorities in order to constitute a data bank. However for the comparison, reactors for which commercial operation starts before July 1974, have been excluded. As far as the main comparative results are concerned, the averages of tritium activity per energy production unit for liquid releases are ranging between 1840 GBq/TWh and 3000 GBq/TWh and two groups of countries may be noted: those for which the results are around 2000 GBq/TWh as FRG, Japan and Switzerland and those which have an activity level around 3000 GBq/TWh as Belgium, France and Sweden. The United States are between these two groups. A factor which may provide an explanation for these discrepancies concerns practices for primary circuit: recycling it, leads to a lower tritium activity for releases and to a higher tritium activity concentration in the primary circuit. Excluding tritium, mean liquid activities per reactor are widely varying from one country to another: - lower than 0,05 GBq in Japan and in Switzerland; - from one thousand to two thousand times higher in France, Sweden and the United States. Discrepancies for gaseous activities are narrower: a factor of 40 in noble gases activities and a factor of 25 for halogens and aerosols activities. In conclusion, for activities of the tritium liquid as well as activities of all other types of radionuclides, countries can be shared in two groups according the activity level - For the lowest: FRG, Japan and Switzerland; - For the highest: Belgium, France and Sweden

  18. Gaseous losses of fertilizer nitrogen from soils under various conditions

    International Nuclear Information System (INIS)

    Smirnov, P.M.; Pedishyus, R.K.

    1974-01-01

    Effects of aerobic and anaerobic conditions; pH, and soil sterilization on the nitrogen loss from ( 15 NH 4 ) 2 SO 4 , Ca( 15 NO 3 ) 2 and Na 15 NO 2 have been studied in vitro. Composition of the liberated gases has been determined by the adsorption chromatography technique. Gaseous losses of fertilizer nitrogen are shown to proceed most intensely during first 10 to 30 days after nitrogen application, Ca(NO 3 ) 2 nitrogen loss being much higher than that of (NH 4 ) 2 SO 4 . Under anaerobic conditions nitrogen losses are markedly higher than in the presence of oxygen. Nitrogen of Ca(NO 3 ) 2 and (NH 4 ) 2 SO 4 is lost mainly as N 2 O and N 2 , the proportion of NO and NO 2 under aerobic and, particularly, anaerobic conditions is very small. Fertilizer type and aeration affect strongly the composition of liberated gases and the N 2 O:N 2 ratio. Under anaerobic conditions, Ca(NO 3 ) 2 nitrogen, beginning from the first days, is lost mainly as N 2 (75-80%), N 2 O makes up only 12 to 14%. Under aerobic conditions, (NH 4 ) 2 SO 4 and Ca(NO 3 ) 2 release initially a considerable amount of N 2 O, its reduction to N 2 being inhibited. In the course of time, however, a noticeable growth of the N 2 fraction occurs and it is accompanied by the decrease in N 2 O. Soil pH effects are related mainly to the composition of gases released rather than to the total nitrogen loss by Ca(NO 3 ) 2 . Under anaerobic conditions, more reduced gaseous products N 2 O and N 2 - are formed at acidic and neutral soil reaction, the amount of N 2 being greater at pH 7 than at pH 4.4. Under aerobic conditions, Ca(NO 3 ) 2 at pH 7 loses nitrogen mostly as N 2 , while under acidic soil reaction (pH 4.1-4.4) the losses occur as N 2 O and in part as NO and NO 2 . Sterilized soil at acidic pH liberates primarily nitrogen oxide which is formed apparently as a result of chemical reactions with participation of nitrites

  19. Particle and gaseous emissions from individual diesel and CNG buses

    Directory of Open Access Journals (Sweden)

    Å. M. Hallquist

    2013-05-01

    Full Text Available In this study size-resolved particle and gaseous emissions from 28 individual diesel-fuelled and 7 compressed natural gas (CNG-fuelled buses, selected from an in-use bus fleet, were characterised for real-world dilution scenarios. The method used was based on using CO2 as a tracer of exhaust gas dilution. The particles were sampled by using an extractive sampling method and analysed with high time resolution instrumentation EEPS (10 Hz and CO2 with a non-dispersive infrared gas analyser (LI-840, LI-COR Inc. 1 Hz. The gaseous constituents (CO, HC and NO were measured by using a remote sensing device (AccuScan RSD 3000, Environmental System Products Inc.. Nitrogen oxides, NOx, were estimated from NO by using default NO2/NOx ratios from the road vehicle emission model HBEFA3.1. The buses studied were diesel-fuelled Euro III–V and CNG-fuelled Enhanced Environmentally Friendly Vehicles (EEVs with different after-treatment, including selective catalytic reduction (SCR, exhaust gas recirculation (EGR and with and without diesel particulate filter (DPF. The primary driving mode applied in this study was accelerating mode. However, regarding the particle emissions also a constant speed mode was analysed. The investigated CNG buses emitted on average a higher number of particles but less mass compared to the diesel-fuelled buses. Emission factors for number of particles (EFPN were EFPN, DPF = 4.4 ± 3.5 × 1014, EFPN, no DPF = 2.1 ± 1.0 × 1015 and EFPN, CNG = 7.8 ± 5.7 ×1015 kg fuel−1. In the accelerating mode, size-resolved emission factors (EFs showed unimodal number size distributions with peak diameters of 70–90 nm and 10 nm for diesel and CNG buses, respectively. For the constant speed mode, bimodal average number size distributions were obtained for the diesel buses with peak modes of ~10 nm and ~60 nm. Emission factors for NOx expressed as NO2 equivalents for the diesel buses were on average 27 ± 7 g (kg fuel−1 and for the CNG buses 41

  20. Nitrification inhibitors mitigated reactive gaseous nitrogen intensity in intensive vegetable soils from China.

    Science.gov (United States)

    Fan, Changhua; Li, Bo; Xiong, Zhengqin

    2018-01-15

    Nitrification inhibitors, a promising tool for reducing nitrous oxide (N 2 O) losses and promoting nitrogen use efficiency by slowing nitrification, have gained extensive attention worldwide. However, there have been few attempts to explore the broad responses of multiple reactive gaseous nitrogen emissions of N 2 O, nitric oxide (NO) and ammonia (NH 3 ) and vegetable yield to nitrification inhibitor applications across intensive vegetable soils in China. A greenhouse pot experiment with five consecutive vegetable crops was performed to assess the efficacies of two nitrification inhibitors, namely, nitrapyrin and dicyandiamide on reactive gaseous nitrogen emissions, vegetable yield and reactive gaseous nitrogen intensity in four typical vegetable soils representing the intensive vegetable cropping systems across mainland China: an Acrisol from Hunan Province, an Anthrosol from Shanxi Province, a Cambisol from Shandong Province and a Phaeozem from Heilongjiang Province. The results showed soil type had significant influences on reactive gaseous nitrogen intensity, with reactive gaseous nitrogen emissions and yield mainly driven by soil factors: pH, nitrate, C:N ratio, cation exchange capacity and microbial biomass carbon. The highest reactive gaseous nitrogen emissions and reactive gaseous nitrogen intensity were in Acrisol while the highest vegetable yield occurred in Phaeozem. Nitrification inhibitor applications decreased N 2 O and NO emissions by 1.8-61.0% and 0.8-79.5%, respectively, but promoted NH 3 volatilization by 3.2-44.6% across all soils. Furthermore, significant positive correlations were observed between inhibited N 2 O+NO and stimulated NH 3 emissions with nitrification inhibitor additions across all soils, indicating that reduced nitrification posed the threat of NH 3 losses. Additionally, reactive gaseous nitrogen intensity was significantly reduced in the Anthrosol and Cambisol due to the reduced reactive gaseous nitrogen emissions and increased

  1. Germination of Avena fatua under different gaseous environments

    Energy Technology Data Exchange (ETDEWEB)

    Hart, J.W.; Berrie, A.M.M.

    1966-01-01

    The atmosphere in which seeds germinate can profoundly affect the level of germination and dormancy. Seeds were germinated in atmospheres containing various concentrations of carbon dioxide and oxygen. At the same time the effect of light on these systems was examined. The germination of partially dormant populations of wild oat seed is inhibited by white light. This response to light is most apparent when the caryopsis is enclosed in the pales. Investigations into the effect of the ambient atmosphere on germination have indicated that, while oxygen is a necessary factor in the germination of this species, carbon dioxide also has an effect. A lack of carbon dioxide increases the degree of light inhibition of germination; 3% carbon dioxide (by volume) allows germination in light; 20% carbon dioxide inhibits germination in light and darkness at all tested oxygen concentrations.

  2. Combination of ozone feed and wet electrostatic precipitator. Experimental study of an innovative system to filter gaseous iodine and iodine containing particles

    International Nuclear Information System (INIS)

    Gouëllo, Mélany; Hokkinen, Jouni; Kärkelä, Teemu; Auvinen, Ari

    2017-01-01

    Efficient mitigation systems capable of reducing as much as possible the radioactive discharge to the environment in a severe Nuclear Power Plant (NPP) accident are a necessity. Nuclear Power Plants are equipped with filtration systems which have been characterized for aerosol retention in a short term, but to a far lesser extent for the retention of volatile iodine or for the long-term behaviour of the system. After the Fukushima accident, one of the main concerns of the nuclear industry has been to verify the ability of filtration systems to mitigate the possible source term to the environment. Radiotoxic iodine has a significant contribution to a possible source term in a severe NPP accident. An innovative system has been developed at VTT Technical Research Centre of Finland Ltd. to filter gaseous iodine and iodine containing particles (e.g. I x O y ). The system consists of a combination of an ozone feed and a modern wet electrostatic precipitator (WESP). The electrostatic precipitation (ESP) technique is widely used in the industry to filter out impurities (i.e. particles) in gases. The advantage of a WESP is that the impurities are removed from the system with a solution. They can thus directly be transported to a water container, such as the sump in a nuclear power plant. The addition of ozone feed at the inlet of the WESP allows the oxidation of gaseous iodine into particles. The efficiency of the system for the filtration of gaseous molecular iodine and methyl iodine has been tested and the subsequent observations are further discussed in this paper. The results showed that the combination of WESP together with ozone feed results in a good filtering efficiency against molecular iodine under air atmosphere and air/steam atmosphere. (author)

  3. Test set of gaseous analytes at Hanford tank farms

    International Nuclear Information System (INIS)

    1997-01-01

    DOE has stored toxic and radioactive waste materials in large underground tanks. When the vapors in the tank headspaces vent to the open atmosphere a potentially dangerous situation can occur for personnel in the area. An open-path atmospheric pollution monitor is being developed to monitor the open air space above these tanks. In developing this infrared spectra monitor as a safety alert instrument, it is important to know what hazardous gases, called the Analytes of Concern, are most likely to be found in dangerous concentrations. The monitor must consider other gases which could interfere with measurements of the Analytes of Concern. The total list of gases called the Test Set Analytes form the basis for testing the pollution monitor. Prior measurements in 54 tank headspaces have detected 102 toxic air pollutants (TAPs) and over 1000 other analytes. The hazardous Analytes are ranked herein by a Hazardous Atmosphere Rating which combines their measured concentration, their density relative to air, and the concentration at which they become dangerous. The top 20 toxic air pollutants, as ranked by the Hazardous Atmosphere Rating, and the top 20 other analytes, in terms of measured concentrations, are analyzed for possible inclusion in the Test Set Analytes. Of these 40 gases, 20 are selected. To these 20 gases are added the 6 omnipresent atmospheric gases with the highest concentrations, since their spectra could interfere with measurements of the other spectra. The 26 Test Set Analytes are divided into a Primary Set and a Secondary Set. The Primary Set, gases which must be detectable by the monitor, includes the 6 atmospheric gases and the 6 hazardous gases which have been measured at dangerous concentrations. The Secondary Set gases need not be monitored at this time. The infrared spectra indicates that the pollution monitor will detect all 26 Test Set Analytes by thermal emission and will detect 15 Test Set Analytes by laser absorption

  4. The development of gaseous detectors with solid photocathodes for low temperature applications

    CERN Document Server

    Periale, L.; Iacobaeus, C.; Francke, T.; Lund-Jensen, B.; Pavlopoulos, N.; Picchi, P.; Pietropaolo, F.

    2004-01-01

    There are several applications and fundamental research areas which require the detection of VUV light at cryogenic temperatures. For these applications we have developed and successfully tested special designs of gaseous detectors with solid photocathodes able to operate at low temperatures: sealed gaseous detectors with MgF2 windows and windowless detectors. We have experimentally demonstrated, that both primary and secondary (due to the avalanche multiplication inside liquids) scintillation lights could be recorded by photosensitive gaseous detectors. The results of this work may allow one to significantly improve the operation of some noble liquid gas TPCs.

  5. Balance and behavior of gaseous radionuclides released during initial PWR fuel reprocessing operations

    International Nuclear Information System (INIS)

    Leudet, A.; Miquel, P.; Goumondy, P.J.; Charrier, G.

    1982-08-01

    Five fuel pins, taken from a PWR fuel assembly with 32000 MWD/t burn-up were chopped and dissolved in leak-proof equipment designed for accurate determination of the composition and quantity of gaseous elements released in these operations. Analytical methods were specially developped to determine directly the noble gases, tritium and gaseous carbon compounds in the gas phase. Volatile iodine was kept as close as possible to the source by cold traps, then transferred to a caustic solution for quantitative analysis. The quantities and activities of gaseous fission products thus determined were compared with predicted values obtained through computation. Very good agreement was generally observed

  6. Balance and behavior of gaseous radionuclides released during initial PWR fuel reprocessing operations

    International Nuclear Information System (INIS)

    Leudet, A.; Miquel, P.; Goumondy, P.J.; Charrier, G.

    1983-01-01

    Five fuel pins, taken from a PWR fuel assembly with 32,000 MwD/t burn-up were chopped and dissolved in leak-proof equipment designed for accurate determination of the composition and quantity of gaseous elements released in these operations. Analytical methods were specially developed to determine directly the noble gases, tritium and gaseous carbon compounds in the gas phase. Volatile iodine was kept as close as possible to the source by cold traps, then transferred to a caustic solution for quantitative analysis. The quantities and activities of gaseous fission products thus determined were compared with predicted values obtained through computation. Very good agreement was generally observed

  7. Biofuels and Bioproducts from Wet and Gaseous Waste Streams: Challenges and Opportunities

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2017-01-09

    This report draws together activities related to wet and gaseous waste feedstocks into a single document. It enables an amplified focus on feedstocks in the relevant technology and potential markets category. Also, this report helps to inform and support ongoing wet and gaseous resource recovery activities in the Bioenergy Technologies Office (BETO) and in the broader federal space. Historically, the office has identified wet and gaseous waste feedstocks as potentially advantageous, but has not pursued them with a sustained focus. This document seeks to position these waste streams appropriately alongside more traditional feedstocks in BETO efforts.

  8. Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF{sub 6}) in the diffusion cascade

    Energy Technology Data Exchange (ETDEWEB)

    Huffer, J.E. [Parallax, Inc., Atlanta, GA (United States)

    1997-04-01

    This paper determines the nuclear safety of gaseous UF{sub 6} in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF{sub 6} in plant operations..

  9. Rapid monitoring of gaseous fission products in BWRs using a portable spectrometer

    International Nuclear Information System (INIS)

    Yeh, Wei-Wen; Lee, Cheng-Jong; Chen, Chen-Yi; Chung, Chien

    1996-01-01

    Rapid, quantitative determination of gaseous radionuclides is the most difficult task in the field of environmental monitoring for radiation. Although the identification of each gaseous radionuclide is relatively straightforward using its decayed gamma ray as an index, the quantitative measurement is hampered by the time-consuming sample collection procedures, in particular for the radioactive noble gaseous fission products of krypton and xenon. In this work, a field gamma-ray spectrometer consisting of a high-purity germanium detector, portable multichannel anlayzer, and a notebook computer was used to conduct rapid scanning of radioactive krypton and xenon in the air around a nuclear facility

  10. Turbulence enhancement by ultrasonically induced gaseous cavitation in the CO2 saturated water

    International Nuclear Information System (INIS)

    Lee, Seung Youp; Choi, Young Don

    2002-01-01

    Recent primary concern for the design of high performance heat exchanger and highly integrated electronic equipment is to develop an active and creative technologies which enhance the heat transfer without obstructing the coolant flows. In this study, we found through the LDV measurement that the gaseous cavitation induced by ultrasonic vibration applied to the CO 2 saturated water in the square cross-sectioned straight duct flow enhances the turbulence much more than the case of non-ultrasonic or normal ultrasonic conditions without gaseous cavitation does. We also found that gaseous cavitation can enhance effectively the turbulent heat transfer between the heating surfaces and coolants by destructing the viscous sublayer

  11. Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF6) in the diffusion cascade

    International Nuclear Information System (INIS)

    Huffer, J.E.

    1997-04-01

    This paper determines the nuclear safety of gaseous UF 6 in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF 6 in plant operations

  12. Measurement of the Portsmouth Gaseous Diffusion Plant criticality accident alarm

    International Nuclear Information System (INIS)

    Tayloe, R.W. Jr.; D'Aquila, D.M.; McGinnis, R.B.

    1991-01-01

    The nuclear criticality accident radiation alarm system installed at the Portsmouth Gaseous Diffusion Plant was tested extensively at critical facilities located at the Los Alamos National Laboratory. The ability of the neutron scintillator radiation detection units to respond to a minimum accident of concern as defined in Standard ANSI/ANS-83.-1986 was demonstrated. Detector placement and the established trip point are based on shielding calculations performed by the Oak Ridge National Laboratory and criticality specialists at the Portsmouth plant. Based on these experiments and calculations, a detector trip point of 5 mrad/h in air is used. Any credible criticality accident is expected to produce neutron radiation fields >5 mrad/h in air at one or more radiation alarm locations. Each radiation alarm location has a cluster of three detectors that employs a two-out-of-three alarm logic. Earlier work focused on testing the alarm logic latching circuitry. This work was directed toward measurements involving the actual audible alarm signal delivered

  13. Partnering efforts at the Paducah Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Warren, C.B.

    1995-01-01

    Before individuals or agencies can effectively work together to solve common problems, they must first agree on exactly what those problems are and establish common goals and methods that will lead to mutually acceptable solutions. Then, they must make a conscientious effort to form a cohesive team that focuses on the established goals and deemphasize traditional roles, which may in some instances be considered adversarial. This kind of teamwork/partnering process can be more difficult, though not impossible, to achieve in cases where there are traditional (real or imagined) adversarial relationships between the parties, i.e. regulator vs. regulated. The US Department of Energy Site Office (DOE) at Paducah, Kentucky, the Kentucky Department of Environmental Protection (KDEP) and the US Environmental Protection Agency, Region IV (EPA) have made t strides toward teamwork and partnering at DOE's Paducah Gaseous Diffusion Plant. They have accomplished this in a number of ways, which will be discussed in greater detail but first and foremost, the agencies agreed up front that they had mutual goals and interests. These goals are to protect public health and the environment in a cost-effective and timely manner, taking care to make the wisest use of public resources (tax dollars); to evaluate and minimize risks, and to achieve ''Win-Win'' for all parties concerned

  14. Bioavailability study for the Paducah Gaseous Diffusion Plant

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, T.L.; Kszos, L.A.

    1996-08-01

    The overall purpose of this plan is to assess the bioavailability of metals in the continuous and intermittent outfalls. The results may be used to determine alternative metal limits that more appropriately measure the portion of metal present necessary for toxicity to aquatic life. These limits must remain protective of in-stream aquatic life; thus, the highest concentration of metal in the water will be determined concurrently with an assessment of acute or chronic toxicity on laboratory tests. Using the method developed by the Kentucky Division of Water (KDOW), biomonitoring results and chemical data will be used to recommend alternative metal limits for the outfalls of concern. The data will be used to meet the objectives of the study: (1) evaluate the toxicity of continuous outfalls and intermittent outfalls at Paducah Gaseous Diffusion Plant; (2) determine the mean ratio of dissolved to Total Recoverable metal for Cd, Cr, Cu, Pb, Ni, and Zn in the continuous and intermittent outfalls; (3) determine whether the concentration of total recoverable metal discharged causes toxicity to fathead minnows and /or Ceriodaphnia; and (4) determine alternative metal limits for each metal of concern (Cd, Cr, Cu, Pb, Ni, and Zn).

  15. Gaseous saturable absorbers for the Helios CO2 laser system

    International Nuclear Information System (INIS)

    Haglund, R.F. Jr.; Nowak, A.V.; Czuchlewski, S.J.

    1981-01-01

    Saturable absorbers are widely used to suppress parasitic oscillations in large-aperture, high-power CO 2 fusion-laser systems. We report experimental results on SF 6 -based gaseous saturable absorbers used for parasitic suppression in the eight-beam, 10 kJ Helios fusion-laser system. The gas mix effectively quenches self-lasing in the 9 and 10 μm branches of the CO 2 laser spectrum while simultaneously allowing high transmission of subnanosecond multiwavelength pulses for target-irradiation experiments. The gas isolator now in use consists of SF 6 and the additional fluorocarbons: 1, 1-difluoroethane (FC-152a); dichlorodifluoromethane (FC-12); chloropentafluoroethane (FC-115); 1,1-dichloro 2,2-difluoroethylene (FC-1112a); chlorotrifluoroethylene (FC-1113); and perfluorocyclobutane (FC-C318). The saturation of the mix was studied as a function of incident fluence, pressure, cell length, and incident wavelength. Experimental results are presented on the saturation properties of pure SF 6 and FC-152a and compared with the saturation behavior of CO 2 at 400 0 C

  16. Nuclear piston engine and pulsed gaseous core reactor power systems

    International Nuclear Information System (INIS)

    Dugan, E.T.

    1976-01-01

    The investigated nuclear piston engines consist of a pulsed, gaseous core reactor enclosed by a moderating-reflecting cylinder and piston assembly and operate on a thermodynamic cycle similar to the internal combustion engine. The primary working fluid is a mixture of uranium hexafluoride, UF 6 , and helium, He, gases. Highly enriched UF 6 gas is the reactor fuel. The helium is added to enhance the thermodynamic and heat transfer characteristics of the primary working fluid and also to provide a neutron flux flattening effect in the cylindrical core. Two and four-stroke engines have been studied in which a neutron source is the counterpart of the sparkplug in the internal combustion engine. The piston motions which have been investigated include pure simple harmonic, simple harmonic with dwell periods, and simple harmonic in combination with non-simple harmonic motion. The results of the conducted investigations indicate good performance potential for the nuclear piston engine with overall efficiencies of as high as 50 percent for nuclear piston engine power generating units of from 10 to 50 Mw(e) capacity. Larger plants can be conceptually designed by increasing the number of pistons, with the mechanical complexity and physical size as the probable limiting factors. The primary uses for such power systems would be for small mobile and fixed ground-based power generation (especially for peaking units for electrical utilities) and also for nautical propulsion and ship power

  17. Determination of gaseous compounds using online mass spectrometry

    International Nuclear Information System (INIS)

    Praun, S.

    1999-08-01

    The work is divided in three major parts and describes various measurements of gaseous compounds. The first part tasks the problem of transit traffic along the motorway from Kufstein, Northern Tyrol/Austria until Ala, Trentino/Italy. During three periods measurements of the immissions of many compounds were carried out simultaneously in Northern Tyrol, Southern Tyrol and Trentino. The influence of the ban of heavy lorry traffic during the weekend and during the night on the reduction of NO 2 could be demonstrated. Furthermore certain compounds (e.g. Benzene) were monitored online for the first time along the motorway at lowest concentrations using the mass spectrometer 'Airsense 500'. In the second part online measurements of exhaled human breath after the oral application of a medicine against bronchitis was performed. In that way beside clinical and pharmacological studies the effectiveness of this pharmacon could be proved. The last part of the present work shows adsorption- and desorption measurements on four different adsorbents. During this procedure seven different gases with an increasing number of carbon atoms were monitored online by the hyphenation of these adsorbents with the mass spectrometer 'Airsense 500'. Thereby, the various properties of the adsorbents in the interaction with the gases could be demonstrated. (author)

  18. Innovative Decontamination Technology for Use in Gaseous Diffusion Plant Decommissioning

    International Nuclear Information System (INIS)

    Peters, M.J.; Norton, C.J.; Fraikor, G.B.; Potter, G.L.; Chang, K.C.

    2006-01-01

    The results of bench scale tests demonstrated that TechXtract R RadPro TM technology (hereinafter referred to as RadPro R ) can provide 100% coverage of complex mockup gaseous diffusion plant (GDP) equipment and can decontaminate uranium (U) deposits with 98% to 99.99% efficiency. Deployment tests demonstrated RadPro R can be applied as foam, mist/fog, or steam, and fully cover the internal surfaces of complex mockup equipment, including large piping. Decontamination tests demonstrated that two formulations of RadPro R , one with neutron attenuators and one without neutron attenuators, could remove up to 99.99% of uranyl fluoride deposits, one of the most difficult to remove deposits in GDP equipment. These results were supplemented by results from previous tests conducted in 1994 that showed RadPro R could remove >97% of U and Tc-99 contamination from actual GDP components. Operational use of RadPro R at other DOE and commercial facilities also support these data. (authors)

  19. Nitrogen-system safety study: Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    1982-07-01

    The Department of Energy has primary responsibility for the safety of operations at DOE-owned nuclear facilities. The guidelines for the analysis of credible accidents are outlined in DOE Order 5481.1. DOE has requested that existing plant facilities and operations be reviewed for potential safety problems not covered by standard industrial safety procedures. This review is being conducted by investigating individual facilities and documenting the results in Safety Study Reports which will be compiled to form the Existing Plant Final Safety Analysis Report which is scheduled for completion in September, 1984. This Safety Study documents the review of the Plant Nitrogen System facilities and operations and consists of Section 4.0, Facility and Process Description, and Section 5.0, Accident Analysis, of the Final Safety Analysis Report format. The existing nitrogen system consists of a Superior Air Products Company Type D Nitrogen Plant, nitrogen storage facilities, vaporization facilities and a distribution system. The system is designed to generate and distribute nitrogen gas used in the cascade for seal feed, buffer systems, and for servicing equipment when exceptionally low dew points are required. Gaseous nitrogen is also distributed to various process auxiliary buildings. The average usage is approximately 130,000 standard cubic feet per day

  20. Gaseous diffusion flames: simple structures and their interaction

    Energy Technology Data Exchange (ETDEWEB)

    Cavaliere, A. [Universita degli Studi Federico II, Naples (Italy). Dip. di Ingegneria Chimica; Ragucci, R. [Istituto di Ricerche sulla Combustione C,N.R., Naples (Italy)

    2001-07-01

    This is a synoptic overview of a selection of works dealing with single diffusive structures, with their mutual interaction in simple flows and their statistical modeling in complex flows. The focus is on reacting conditions pertaining to gaseous diffusion flames, but isothermal structures are also described when they are of some conceptual interest. This paper considers only few representative works for each subject, which are functional in explaining the key characteristics of the diffusive structures. The extension, given to single subjects, is not weighed according to the number of related publications but on the relevance to the basic understanding of the general framework concerning diffusion flames. One-dimensional structures are first discussed. They are ordered according to the number of balance equation terms needed for their description. Two-dimensional (2D) structures are then introduced following an order based on their convolution level. Some pioneering work on three-dimensional structures is further quoted. The temporal evolution of simple structures in quiescent or simple flowing 2D systems is considered. The latter case is exploited to present classification of diffusion-controlled mixing regimes. Modeling characterization approach of turbulent diffusion flames is also described in order to yield a self-sufficient didactic presentation. The approach based on the flame surface density model is specifically discussed because of its potential use in the determination of qualitative and quantitative features of simple diffusion flames. (author)

  1. Contamination of liquid oxygen by pressurized gaseous nitrogen

    Science.gov (United States)

    Zuckerwar, Allan J.; King, Tracy K.; Ngo, Kim Chi

    1989-01-01

    The penetration of pressurized gaseous nitrogen (GN2) into liquid oxygen (LOX) was investigated experimentally in the 7-inch High Temperature Tunnel, the pilot tunnel for the 8-foot High Temperature Tunnel (8'HTT) at Langley Research Center. A preliminary test using a nuclear monitor revealed the extent of the liquid nitrogen (LN2) build-up at the LOX interface as a function of GN2 pressure. Then an adaptation of the differential flash vaporization technique was used to determine the binary diffusivity of the LOX-LN2 system at a temperature of 90.2 K. The measured value D equals 0.000086 sq cm/s + or - 25 percent together with two prior measurements at lower temperatures revealed an excellent fit to the Arrhenius equation, yielding a pre-exponential factor D sub 0 equals 0.0452 sq cm/s and an activation enthalpy H equals 1.08 kcal/mol. At a pressure of 1700 psi and holding time of 15 min, the penetration of LN2 into LOX (to a 1 percent contamination level) was found to be 0.9 cm, indicating but minimal impact upon 8'HTT operations.

  2. Gaseous mercury fluxes from the forest floor of the Adirondacks

    International Nuclear Information System (INIS)

    Choi, Hyun-Deok; Holsen, Thomas M.

    2009-01-01

    The flux of gaseous elemental mercury (Hg 0 ) from the forest floor of the Adirondack Mountains in New York (USA) was measured numerous times throughout 2005 and 2006 using a polycarbonate dynamic flux chamber (DFC). The Hg flux ranged between -2.5 and 27.2 ng m -2 h -1 and was positively correlated with temperature and solar radiation. The measured Hg emission flux was highest in spring, and summer, and lowest in winter. During leaf-off periods, the Hg emission flux was highly dependent on solar radiation and less dependent on temperature. During leaf-on periods, the Hg emission flux was fairly constant because the forest canopy was shading the forest floor. Two empirical models were developed to estimate yearly Hg 0 emissions, one for the leaf-off period and one for the leaf-on period. Using the U.S. EPA's CASTNET meteorological data, the cumulative estimated emission flux was approx. 7.0 μg Hg 0 m -2 year -1 . - Empirical models based on the Hg emission measurements from the forest floor of the Adirondacks indicate the estimated emission flux was approx. 7.0 μg Hg 0 m -2 year -1 in 2006

  3. Preview-based sampling for controlling gaseous simulations

    KAUST Repository

    Huang, Ruoguan

    2011-01-01

    In this work, we describe an automated method for directing the control of a high resolution gaseous fluid simulation based on the results of a lower resolution preview simulation. Small variations in accuracy between low and high resolution grids can lead to divergent simulations, which is problematic for those wanting to achieve a desired behavior. Our goal is to provide a simple method for ensuring that the high resolution simulation matches key properties from the lower resolution simulation. We first let a user specify a fast, coarse simulation that will be used for guidance. Our automated method samples the data to be matched at various positions and scales in the simulation, or allows the user to identify key portions of the simulation to maintain. During the high resolution simulation, a matching process ensures that the properties sampled from the low resolution simulation are maintained. This matching process keeps the different resolution simulations aligned even for complex systems, and can ensure consistency of not only the velocity field, but also advected scalar values. Because the final simulation is naturally similar to the preview simulation, only minor controlling adjustments are needed, allowing a simpler control method than that used in prior keyframing approaches. Copyright © 2011 by the Association for Computing Machinery, Inc.

  4. Photoresist removal using gaseous sulfur trioxide cleaning technology

    Science.gov (United States)

    Del Puppo, Helene; Bocian, Paul B.; Waleh, Ahmad

    1999-06-01

    A novel cleaning method for removing photoresists and organic polymers from semiconductor wafers is described. This non-plasma method uses anhydrous sulfur trioxide gas in a two-step process, during which, the substrate is first exposed to SO3 vapor at relatively low temperatures and then is rinsed with de-ionized water. The process is radically different from conventional plasma-ashing methods in that the photoresist is not etched or removed during the exposure to SO3. Rather, the removal of the modified photoresist takes place during the subsequent DI-water rinse step. The SO3 process completely removes photoresist and polymer residues in many post-etch applications. Additional advantages of the process are absence of halogen gases and elimination of the need for other solvents and wet chemicals. The process also enjoys a very low cost of ownership and has minimal environmental impact. The SEM and SIMS surface analysis results are presented to show the effectiveness of gaseous SO3 process after polysilicon, metal an oxide etch applications. The effects of both chlorine- and fluorine-based plasma chemistries on resist removal are described.

  5. Tensile properties of ADI material in water and gaseous environments

    Energy Technology Data Exchange (ETDEWEB)

    Rajnovic, Dragan, E-mail: draganr@uns.ac.rs [Faculty of Technical Sciences, University of Novi Sad, Trg D. Obradovića 6, 21000 Novi Sad (Serbia); Balos, Sebastian; Sidjanin, Leposava [Faculty of Technical Sciences, University of Novi Sad, Trg D. Obradovića 6, 21000 Novi Sad (Serbia); Eric Cekic, Olivera [Innovation Centre, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade (Serbia); Grbovic Novakovic, Jasmina [Vinca Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

    2015-03-15

    Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, having comparable mechanical properties as forged steels. However, it was found that in contact with water the mechanical properties of austempered ductile irons decrease, especially their ductility. Despite considerable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that hydrogen or small atom chemisorption causes the weakening of the surface atomic bonds. To get additional reliable data of that phenomenon, in this paper, two different types of austempered ductile irons were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was found that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Furthermore, the fracture surface analysis revealed that the morphology of the embrittled zone near the specimen surface shares similarities to the fatigue micro-containing striation-like lines, which indicates that the morphology of the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture. - Highlights: • In contact with water and other liquids the ADI suddenly exhibits embrittlement. • The embrittlement is more pronounced in water than in the gaseous hydrogen. • The hydrogen chemisorption into ADI surface causes the formation of a brittle zone. • The ADI austempered at lower temperatures (300 °C) is more resistant to embrittlement.

  6. Raffinate treatment at the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Acox, T.A.

    1983-01-01

    Raffinate solutions, which contain uranium, technetium, nitrates, and lesser amounts of heavy metals, are produced in the decontamination and uranium recovery operations at the Portsmouth Gaseous Diffusion Plant. These solutions are presently being placed in temporary storage until three treatment facilities are constructed which will produce an environmentally acceptable effluent from the raffinate. These facilities are: (1) The Heavy Metals Precipitation Facility; (2) The Technetium Ion Exchange Facility; and (3) The Biodenitrification Pilot Plant. When the facilities are completed, the raffinate will be treated in 500 gallon batches. The first treatment is the heavy metals precipitation by caustic addition and filtering. The effluent proceeds to the ion exchange columns where the technetium is removed by adsorption onto a strongly basic, anion exchange resin which has been converted to the hydroxyl form. Following ion exchange, the solution is transported to the biodenitrification pilot plant. The biodenitrification column is a fluidized-bed using bacteria-laden coal particles as the denitrifying media. The resulting effluent should meet the limits established by the US EPA for all metals and nitrate. Technetium will be 98+% removed and the uranium concentration will be less than one milligram per liter. 13 references

  7. Isotope exchange between gaseous hydrogen and uranium hydride powder

    International Nuclear Information System (INIS)

    Shugard, Andrew D.; Buffleben, George M.; Johnson, Terry A.; Robinson, David B.

    2014-01-01

    Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

  8. Garden hose separation of gaseous isotopes. Part II. Supersonic accelerations

    International Nuclear Information System (INIS)

    Wang, C.G.; Davis, A.G.M.

    1979-01-01

    A mechanical process for separating gaseous mixtures according to their respective molecular weights, by a variation of the time-of-flight process, is proposed. The separative apparatus consists of several sets of nozzle-deflector combinations surrounded by a stationary collector housed in an evacuated chamber. From a rotating supersonic nozzle, a contiguous plurality of successive groups of molecules is ejected to form a continuous stream of the mixture. The molecules of each group of molecules are allowed to accelerate for a predetermined period of time following their supersonic expansion, thereby allowing each group of molecules to form a generally spherical configuration, the outer radius of which will be enriched in molecules of lighter mass, relative to lesser radii. A deflector means co-rotating with the nozzle is used to deflect molecules that have been allowed to move for the predetermined period of time in accordance with their expansion velocities, from at least one desired portion of the stream, and a stationary collector means is disposed to receive the deflected molecules. The estimated separative work produced from such a unit is about the same or better than that of a modern giant diffuser of similar dimensions. However, with an essentially empty chamber, the unit capital cost as well as the energy required is competitive with any of the well-known methods, mechanical or otherwise

  9. GASEOUS CO ABUNDANCE-AN EVOLUTIONARY TRACER FOR MOLECULAR CLOUDS

    Energy Technology Data Exchange (ETDEWEB)

    Liu Tie; Wu Yuefang; Zhang Huawei, E-mail: liutiepku@gmail.com, E-mail: ywu@pku.edu.cn [Department of Astronomy, Peking University, Beijing 100871 (China)

    2013-09-20

    Planck cold clumps are among the most promising objects to investigate the initial conditions of the evolution of molecular clouds. In this work, by combing the dust emission data from the survey of the Planck satellite with the molecular data of {sup 12}CO/{sup 13}CO/C{sup 18}O (1-0) lines from observations with the Purple Mountain Observatory 13.7 m telescope, we investigate the CO abundance, CO depletion, and CO-to-H{sub 2} conversion factor of 674 clumps in the early cold cores sample. The median and mean values of the CO abundance are 0.89 Multiplication-Sign 10{sup -4} and 1.28 Multiplication-Sign 10{sup -4}, respectively. The mean and median of CO depletion factor are 1.7 and 0.9, respectively. The median value of X{sub CO-to-H{sub 2}} for the whole sample is 2.8 Multiplication-Sign 10{sup 20} cm{sup -2} K{sup -1} km{sup -1} s. The CO abundance, CO depletion factor, and CO-to-H{sub 2} conversion factor are strongly (anti-)correlated to other physical parameters (e.g., dust temperature, dust emissivity spectral index, column density, volume density, and luminosity-to-mass ratio). To conclude, the gaseous CO abundance can be used as an evolutionary tracer for molecular clouds.

  10. GASEOUS CO ABUNDANCE—AN EVOLUTIONARY TRACER FOR MOLECULAR CLOUDS

    International Nuclear Information System (INIS)

    Liu Tie; Wu Yuefang; Zhang Huawei

    2013-01-01

    Planck cold clumps are among the most promising objects to investigate the initial conditions of the evolution of molecular clouds. In this work, by combing the dust emission data from the survey of the Planck satellite with the molecular data of 12 CO/ 13 CO/C 18 O (1-0) lines from observations with the Purple Mountain Observatory 13.7 m telescope, we investigate the CO abundance, CO depletion, and CO-to-H 2 conversion factor of 674 clumps in the early cold cores sample. The median and mean values of the CO abundance are 0.89 × 10 –4 and 1.28 × 10 –4 , respectively. The mean and median of CO depletion factor are 1.7 and 0.9, respectively. The median value of X CO-to-H 2 for the whole sample is 2.8 × 10 20 cm –2 K –1 km –1 s. The CO abundance, CO depletion factor, and CO-to-H 2 conversion factor are strongly (anti-)correlated to other physical parameters (e.g., dust temperature, dust emissivity spectral index, column density, volume density, and luminosity-to-mass ratio). To conclude, the gaseous CO abundance can be used as an evolutionary tracer for molecular clouds

  11. He I lambda 584 in quasars and gaseous nebulae

    International Nuclear Information System (INIS)

    Ferland, G.J.

    1980-01-01

    The He I Lα lambda 584 transfer problem for gaseous nebulae is investigated. Realistic photo-ionization models of quasar clouds and planetary nebulae are combined with the Monte Carlo line transfer technique to determine both the efficiency of destruction of lambda 584 by photo-ionization of hydrogen and the mean number of scatterings undergone before destruction. It is found that large fractions (approximately > 90 per cent) of the lambda 584 photons are destroyed before escaping in all cases considered. Nonetheless, the He I lambda lambda 584, 626 doublet should be present in high redshift quasars with an observed equivalent width of approximately 1 A. Detection of this doublet would provide the only clear indication of the presence or absence of a low density narrow line region for objects in which optical forbidden lines have been redshifted beyond the optical window. The strength of the He I 2 1 S-2 1 P 2.0 μm line is predicted to be approximately 4 times stronger than is actually observed in the planetary nebulae NGC 7027. This suggests that dust is embedded in the ionized gas and causes additional destruction of lambda 584. Finally, the calculations show that photo-ionization model calculations can safely assume nearly complete on-the-spot destruction of lambda 584. The common assumption that the He I singlets are formed in case B conditions is examined in an appendix. (author)

  12. Preliminary analysis of public dose from CFETR gaseous tritium release

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Baojie [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Ni, Muyi, E-mail: muyi.ni@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Lian, Chao; Jiang, Jieqiong [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)

    2015-02-15

    Highlights: • Present the amounts and limit dose of tritium release to the environment for CFETR. • Perform a preliminary simulation of radiation dose for gaseous tritium release. • Key parameters about soil types, wind speed, stability class, effective release height and age were sensitivity analyzed. • Tritium release amount is recalculated consistently with dose limit in Chinese regulation for CFETR. - Abstract: To demonstrate tritium self-sufficiency and other engineering issues, the scientific conception of Chinese Fusion Engineering Test Reactor (CFETR) has been proposed in China parallel with ITER and before DEMO reactor. Tritium environmental safety for CFETR is an important issue and must be evaluated because of the huge amounts of tritium cycling in reactor. In this work, different tritium release scenarios of CFETR and dose limit regulations in China are introduced. And the public dose is preliminarily analyzed under normal and accidental events. Furthermore, after finishing the sensitivity analysis of key input parameters, the public dose is reevaluated based on extreme parameters. Finally, tritium release amount is recalculated consistently with the dose limit in Chinese regulation for CFETR, which would provide a reference for tritium system design of CFETR.

  13. Paducah Gaseous Diffusion Plant Northwest Plume interceptor system evaluation

    International Nuclear Information System (INIS)

    Laase, A.D.; Clausen, J.L.

    1998-01-01

    The Paducah Gaseous Diffusion Plant (PGDP) recently installed an interceptor system consisting of four wells, evenly divided between two well fields, to contain the Northwest Plume. As stated in the Northwest Plume Record of Decision (ROD), groundwater will be pumped at a rate to reduce further contamination and initiate control of the northwest contaminant plume. The objective of this evaluation was to determine the optimum (minimal) well field pumping rates required for plume hotspot containment. Plume hotspot, as defined in the Northwest Plume ROD and throughout this report, is that portion of the plume with trichloroethene (TCE) concentrations greater than 1,000 microg/L. An existing 3-dimensional groundwater model was modified and used to perform capture zone analyses of the north and south interceptor system well fields. Model results suggest that the plume hotspot is not contained at the system design pumping rate of 100 gallons per minute (gal/min) per well field. Rather, the modeling determined that north and south well field pumping rates of 400 and 150 gal/min, respectively, are necessary for plume hotspot containment. The difference between the design and optimal pumping rates required for containment can be attributed to the discovery of a highly transmissive zone in the vicinity of the two well fields

  14. Enamel and dentin bond strength following gaseous ozone application.

    Science.gov (United States)

    Cadenaro, Milena; Delise, Chiara; Antoniollo, Francesca; Navarra, Ottavia Chiara; Di Lenarda, Roberto; Breschi, Lorenzo

    2009-08-01

    To evaluate the effects of gaseous ozone application on enamel and dentin bond strength produced by two self-etching adhesive systems. The shear bond strength test was conducted to assess adhesion on enamel (protocol 1), while the microtensile bond strength test was performed on dentin (protocol 2). Protocol 1: 96 bovine incisors were randomly divided into 4 groups, and enamel surfaces were bonded in accordance with the following treatments: (1E) ozone + Clearfil Protect Bond; (2E) Clearfil Protect Bond (control); (3E) ozone + Xeno III; (4E) Xeno III (control). Ozone gas was applied for 80 s. Shear bond strength was measured with a universal testing machine. Protocol 2: 40 noncarious human molars were selected. Middle/deep dentin was exposed and bonded in accordance with the following treatments: (1D) ozone+Clearfil Protect Bond; (2D) Clearfil Protect Bond (control); (3D) ozone+Xeno III (4D) Xeno III (control). Four-mm-thick buildups were built on the adhesives, then specimens were sectioned in accordance with the nontrimming technique. Specimens were stressed until failure occurred, and failure modes were analyzed. Shear bond and microtensile bond strength data were analyzed using two-way ANOVA and Tukey's post-hoc test. No statistical differences were found between ozone treated specimens and controls, neither on enamel nor on dentin irrespective of the tested adhesive. Clearfil Protect Bond showed higher bond strength to enamel than Xeno III, irrespective of the ozone treatment (p enamel and dentin bond strength.

  15. Process for recovering xenon from radioactive gaseous wastes

    International Nuclear Information System (INIS)

    Kishimoto, Tsuneo.

    1980-01-01

    Purpose: To recover pure xenon economically and efficiently by amply removing radioactive krypton mixed in xenon without changing the rectifying capacity of an xenon rectifying system itself. Method: Xe containing radioactive Kr(Kr-85) is rectified to reduce the concentration of radioactive Kr. Thereafter, non-radioactive Kr or Ar is added to Xe and further the rectification is carried out. The raw material Xe from the Xe adsorption system of, for example, a radioactive gaseous waste disposal system is cooled to about 100 0 C by a heat-exchanger and thereafter supplied to a rectifying tower to carry out normal rectification of Xe thereby to reduce the concentration of Kr contained in Xe at the tower bottom to the rectification limit concentration. Then, non-radioactive Kr is supplied via a precooler to the tower bottom to continue the rectification, thus the Xe fractions at the tower bottom, in which the concentration of radioactive Kr is reduced, being compressed and recovered. (Kamimura, M.)

  16. IAEA verification experiment at the Portsmouth Gaseous Diffusion Plant

    International Nuclear Information System (INIS)

    Gordon, D.M.; Subudhi, M.; Calvert, O.L.; Bonner, T.N.; Cherry, R.C.; Whiting, N.E.

    1998-01-01

    In April 1996, the United States (US) added the Portsmouth Gaseous Diffusion Plant to the list of facilities eligible for the application of International Atomic Energy Agency (IAEA) safeguards. At that time, the US proposed that the IAEA carry out a Verification Experiment at the plant with respect to the downblending of about 13 metric tons of highly enriched uranium (HEU) in the form of UF 6 . This material is part of the 226 metric tons of fissile material that President Clinton has declared to be excess to US national-security needs and which will be permanently withdrawn from the US nuclear stockpile. In September 1997, the IAEA agreed to carry out this experiment, and during the first three weeks of December 1997, the IAEA verified the design information concerning the downblending process. The plant has been subject to short-notice random inspections since December 17, 1997. This paper provides an overview of the Verification Experiment, the monitoring technologies used in the verification approach, and some of the experience gained to date

  17. Structure of positive streamers inside gaseous bubbles immersed in liquids

    International Nuclear Information System (INIS)

    Babaeva, Natalia Yu; Kushner, Mark J

    2009-01-01

    Electric discharges and streamers in liquids typically proceed through vapour phase channels produced by the streamer or in gaseous bubbles. The bubbles can originate by enthalpy changes produced by the discharge or can be artificially injected into the liquid. Experiments on streamers in bubbles immersed in liquids have shown that the discharge propagates either along the surface of the bubble or through the volume of the bubble as in conventional streamer propagation in air. In this paper we report on results of a computational investigation of streamer propagation through bubbles immersed in liquids. We found that the dielectric constant of the liquid in large part determines the path the streamer takes. Streamers in bubbles immersed in a liquid with a high permittivity preferentially propagate along the surface of the bubble. Liquids with low permittivity can result in the streamer propagating along the axis of the bubble. The permittivity at which this transition occurs is a function of the applied voltage, size of the bubble and the conductivity of the liquid. (fast track communication)

  18. Portsmouth Gaseous Diffusion Plant environmental report for 1989

    Energy Technology Data Exchange (ETDEWEB)

    Turner, J.W. (ed.) (Martin Marietta Energy Systems, Inc., Oak Ridge, TN (USA))

    1990-10-01

    This calendar year 1989 annual report on environmental surveillance of the US Department of Energy's (DOE) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: the Summary, Discussion, and Conclusions (Part 1) and the Data Presentation (Part 2). The objectives of this report are the following: report 1989 monitoring data for the installation and its environs that may have been affected by operations on the plant site, provide reasonably detailed information about the plant site and plant operations, provide detailed information on input and assumptions used in all calculations, provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on plant quality assurance. Routine monitoring and sampling for radiation, radioactive materials, and chemical substances on and off the DOE site are used to document compliance with appropriate standards, to identify trends, to provide information for the public, and to contribute to general environmental knowledge. The surveillance program assists in fulfilling the DOE policy of protecting the public, employees, and environment from harm that could be caused by its activities and reducing negative environmental impacts to the greatest degree practicable. Environmental-monitoring information complements data on specific releases, trends, and summaries. 26 refs.

  19. Exposure to recycled uranium contaminants in gaseous diffusion plants

    International Nuclear Information System (INIS)

    Anderson, Jeri L.; Yiin, James H.; Tseng, Chih-Yu; Apostoaei, A. Iulian

    2017-01-01

    As part of an ongoing study of health effects in a pooled cohort of gaseous diffusion plant workers, organ dose from internal exposure to uranium was evaluated. Due to the introduction of recycled uranium into the plants, there was also potential for exposure to radiologically significant levels of "9"9Tc, "2"3"7Np and "2"3"8","2"3"9Pu. In the evaluation of dose response, these radionuclide exposures could confound the effect of internal uranium. Using urine bioassay data for study subjects reported in facility records, intakes and absorbed dose to bone surface, red bone marrow and kidneys were estimated as these organs were associated with a priori outcomes of interest. Additionally, "9"9Tc intakes and doses were calculated using a new systemic model for technetium and compared to intakes and doses calculated using the current model recommended by the International Commission on Radiological Protection. Organ absorbed doses for the transuranics were significant compared to uranium doses; however, "9"9Tc doses calculated using the new systemic model were significant as well. Use of the new model resulted in an increase in "9"9Tc-related absorbed organ dose of a factor of 8 (red bone marrow) to 30 (bone surface). (authors)

  20. Characteristics and distributions of atmospheric mercury ...

    Science.gov (United States)

    Continuous measurements of speciated atmospheric mercury (Hg), including gaseous elemental mercury (GEM), particulate mercury (PHg), and reactive gaseous mercury (RGM) were conducted in Guizhou Province, southwestern China. Guiyang Power Plant (GPP), Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant (GAP), and Guiyang Forest Park (GFP) in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A) were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/impactor, KCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ± 28.3 ng·m−3 and the lowest 6.1 ± 3.9 ng·m−3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m−3 and the minimum average 55.9 pg·m−3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m−3 was measured at GPP, and the lowest level of 20.5 pg·m−3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pollution dominates RGM. Mercury (Hg) is a persistent hazardous pollutant with adverse effects on human health and wildlife due mainly to bioaccumulation and biomagnification in aquatic food webs (Lindqvist et al. 1991; Schroeder and Munt

  1. Modeling and analyses of postulated UF6 release accidents in gaseous diffusion plant

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.; Dyer, R.H.

    1995-10-01

    Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a postulated accident involving the release of uranium hexafluoride (UF 6 ) into the process building of a gaseous diffusion plant. UF 6 undergoes an exothermic chemical reaction with moisture (H 2 O) in the air to form hydrogen fluoride (HF) and radioactive uranyl fluoride (UO 2 F 2 ). As part of a facility-wide safety evaluation, this study evaluated source terms consisting of UO 2 F 2 as well as HF during a postulated UF 6 release accident in a process building. In the postulated accident scenario, ∼7900 kg (17,500 lb) of hot UF 6 vapor is released over a 5 min period from the process piping into the atmosphere of a large process building. UO 2 F 2 mainly remains as airborne-solid particles (aerosols), and HF is in a vapor form. Some UO 2 F 2 aerosols are removed from the air flow due to gravitational settling. The HF and the remaining UO 2 F 2 are mixed with air and exhausted through the building ventilation system. The MELCOR computer code was selected for simulating aerosols and vapor transport in the process building. MELCOR model was first used to develop a single volume representation of a process building and its results were compared with those from past lumped parameter models specifically developed for studying UF 6 release accidents. Preliminary results indicate that MELCOR predicted results (using a lumped formulation) are comparable with those from previously developed models

  2. Emissions factors for gaseous and particulate pollutants from offshore diesel engine vessels in China

    Science.gov (United States)

    Zhang, F.; Chen, Y.; Tian, C.; Li, J.; Zhang, G.; Matthias, V.

    2015-09-01

    Shipping emissions have significant influence on atmospheric environment as well as human health, especially in coastal areas and the harbor districts. However, the contribution of shipping emissions on the environment in China still need to be clarified especially based on measurement data, with the large number ownership of vessels and the rapid developments of ports, international trade and shipbuilding industry. Pollutants in the gaseous phase (carbon monoxide, sulfur dioxide, nitrogen oxides, total volatile organic compounds) and particle phase (particulate matter, organic carbon, elemental carbon, sulfates, nitrate, ammonia, metals) in the exhaust from three different diesel engine power offshore vessels in China were measured in this study. Concentrations, fuel-based and power-based emissions factors for various operating modes as well as the impact of engine speed on emissions were determined. Observed concentrations and emissions factors for carbon monoxide, nitrogen oxides, total volatile organic compounds, and particulate matter were higher for the low engine power vessel than for the two higher engine power vessels. Fuel-based average emissions factors for all pollutants except sulfur dioxide in the low engine power engineering vessel were significantly higher than that of the previous studies, while for the two higher engine power vessels, the fuel-based average emissions factors for all pollutants were comparable to the results of the previous studies. The fuel-based average emissions factor for nitrogen oxides for the small engine power vessel was more than twice the International Maritime Organization standard, while those for the other two vessels were below the standard. Emissions factors for all three vessels were significantly different during different operating modes. Organic carbon and elemental carbon were the main components of particulate matter, while water-soluble ions and elements were present in trace amounts. Best-fit engine speeds

  3. Molecular Dications in Planetary Atmospheric Escape

    Directory of Open Access Journals (Sweden)

    Stefano Falcinelli

    2016-08-01

    Full Text Available Fundamental properties of multiply charged molecular ions, such as energetics, structure, stability, lifetime and fragmentation dynamics, are relevant to understand and model the behavior of gaseous plasmas as well as ionosphere and astrophysical environments. Experimental determinations of the Kinetic Energy Released (KER for ions originating from dissociations reactions, induced by Coulomb explosion of doubly charged molecular ions (molecular dications produced by double photoionization of CO2, N2O and C2H2 molecules of interest in planetary atmospheres, are reported. The KER measurement as a function of the ultraviolet (UV photon energy in the range of 28–65 eV was extracted from the electron-ion-ion coincidence spectra obtained by using tunable synchrotron radiation coupled with ion imaging techniques at the ELETTRA Synchrotron Light Laboratory Trieste, Italy. These experiments, coupled with a computational analysis based on a Monte Carlo trajectory simulation, allow assessing the probability of escape for simple ionic species in the upper atmosphere of Mars, Venus and Titan. The measured KER in the case of H+, C+, CH+, CH2+, N+, O+, CO+, N2+ and NO+ fragment ions range between 1.0 and 5.5 eV, being large enough to allow these ionic species to participate in the atmospheric escape from such planets into space. In the case of Mars, we suggest a possible explanation for the observed behavior of the O+ and CO22+ ion density profiles.

  4. Laser beam propagation in atmospheric turbulence

    Science.gov (United States)

    Murty, S. S. R.

    1979-01-01

    The optical effects of atmospheric turbulence on the propagation of low power laser beams are reviewed in this paper. The optical effects are produced by the temperature fluctuations which result in fluctuations of the refractive index of air. The commonly-used models of index-of-refraction fluctuations are presented. Laser beams experience fluctuations of beam size, beam position, and intensity distribution within the beam due to refractive turbulence. Some of the observed effects are qualitatively explained by treating the turbulent atmosphere as a collection of moving gaseous lenses of various sizes. Analytical results and experimental verifications of the variance, covariance and probability distribution of intensity fluctuations in weak turbulence are presented. For stronger turbulence, a saturation of the optical scintillations is observed. The saturation of scintillations involves a progressive break-up of the beam into multiple patches; the beam loses some of its lateral coherence. Heterodyne systems operating in a turbulent atmosphere experience a loss of heterodyne signal due to the destruction of coherence.

  5. Apparatus and method for enhanced chemical processing in high pressure and atmospheric plasmas produced by high frequency electromagnetic waves

    Science.gov (United States)

    Efthimion, Philip C.; Helfritch, Dennis J.

    1989-11-28

    An apparatus and method for creating high temperature plasmas for enhanced chemical processing of gaseous fluids, toxic chemicals, and the like, at a wide range of pressures, especially at atmospheric and high pressures includes an electro-magnetic resonator cavity, preferably a reentrant cavity, and a wave guiding structure which connects an electro-magnetic source to the cavity. The cavity includes an intake port and an exhaust port, each having apertures in the conductive walls of the cavity sufficient for the intake of the gaseous fluids and for the discharge of the processed gaseous fluids. The apertures are sufficiently small to prevent the leakage of the electro-magnetic radiation from the cavity. Gaseous fluid flowing from the direction of the electro-magnetic source through the guiding wave structure and into the cavity acts on the plasma to push it away from the guiding wave structure and the electro-magnetic source. The gaseous fluid flow confines the high temperature plasma inside the cavity and allows complete chemical processing of the gaseous fluids at a wide range of pressures.

  6. Atmospheric dry deposition of inorganic and organic nitrogen to the Bay of Bengal: Impact of continental outflow

    Digital Repository Service at National Institute of Oceanography (India)

    Srinivas, B.; Sarin, M.M.; Sarma, V.V.S.S.

    neutralizing species in the atmosphere such as mineral aerosols and sea salts (Pakkanen, 1996). Particulate NH 4 + is derived from gaseous NH 3 , which is supplied to the atmosphere as a result of agricultural activities. Until recently, the principal... of Bengal. In IGP, biomass burning emissions (post-harvest burning of agricultural-waste) is a dominant source of pollutants. In addition, large-scale application of fertilizers (ammonia and urea based) in the agricultural dominated region represent a...

  7. Exchange pattern of gaseous elemental mercury in landfill: mercury deposition under vegetation coverage and interactive effects of multiple meteorological conditions.

    Science.gov (United States)

    Tao, Zhengkai; Liu, Yang; Zhou, Meng; Chai, Xiaoli

    2017-12-01

    Landfill is known as a potential source of atmospheric Hg and an important component of the local or regional atmospheric Hg budget. This study investigated the gaseous elemental Hg surface-air fluxes under differing conditions at a typical municipal solid waste landfill site, highlighting the interactive effects of plant coverage and meteorological conditions. The results indicated that Hg fluxes exhibited a feature represented by diel variation. In particular, Hg deposition was observed under a condition of Kochia sieversiana coverage, whereas emission that occurred after K. sieversiana was removed. Hg emission was the dominant mode under conditions of Setaria viridis coverage and its removal; however, the average Hg emission flux with the S. viridis coverage was nearly four times lower than after its removal. These findings verified that the plant coverage should be a key factor influencing the Hg emission from landfills. In addition, Hg fluxes were correlated positively with solar radiation and air/soil temperature and correlated inversely with relative humidity under all conditions, except K. sieversiana coverage. This suggested that the interactive effects of meteorological conditions and plant coverage played a jointly significant role in the Hg emission from landfills. It was established that K. sieversiana can inhibit Hg emission efficiently, and therefore, it could potentially be suitable for use as a plant-based method to control Hg pollution from landfills.

  8. Gaseous analytes of concern at Hanford Tank Farms. Topical report

    International Nuclear Information System (INIS)

    1996-01-01

    Large amounts of toxic and radioactive waste materials are stored in underground tanks at DOE sites. When the vapors in the tank headspaces vent to the open atmosphere a potentially dangerous situation can occur for personnel in the area. An open-path atmospheric pollution monitor is being developed for DOE to monitor the open air space above these tanks. In developing this monitor it is important to know what hazardous gases are most likely to be found in dangerous concentrations. These gases are called the Analytes of Concern. At the present time, measurements in eight tanks have detected thirty-one analytes in at least two tanks and fifteen analytes in only one tank. In addition to these gases, Carbon tetrachloride is considered to be an Analyte of Concern because it permeates the ground around the tanks. These Analytes are described and ranked according to a Hazard Index which combines their vapor pressure, density, and approximate danger level. The top sixteen ranked analytes which have been detected in at least two tanks comprise an open-quotes Analytes of Concern Test Listclose quotes for determining the system performance of the atmospheric pollution monitor under development. A preliminary examination of the infrared spectra, barring atmospheric interferences, indicates that: The pollution monitor will detect all forty-seven Analytes exclamation point

  9. Contribution to the study of gaseous Carburization of Uranium

    International Nuclear Information System (INIS)

    Esteban Hernandez, J. A.; Jimenez Moreno, J. M.; Villota Ruiz, P. de

    1966-01-01

    Thermal decomposition of uranium hydride powder obtained by hydrogenation of uranium turnings is studied on the first part of this paper. Carburization of the uranium hydride or metallic uranium powder with methane is studied in the second part. A method of uranium monocarbide fabrication under static atmosphere is described. On this method hydrogen is removed by means of an uranium getter. (Author) 6 refs

  10. Spectral solar irradiance and some optical properties for various polluted atmospheres

    International Nuclear Information System (INIS)

    Jacovides, Constantinos P.; Asimakopoulos, Demosthenis N.; Steven, Michael D.

    2000-01-01

    Using ground-based spectroradiometric measurements taken over the Athens atmosphere during May 1995, the influence of gaseous pollutants and aerosol on the spectral radiant energy distribution was investigated. It was found that spectral measurements exhibited variations based on various polluted urban atmospheric conditions as determined via gaseous pollutants record analysis. The relative attenuations cause by gaseous pollutants and aerosol can exceed 27%, 17% and 16% in the global ultraviolet, visible and near-infrared portions of the solar spectrum respectively, as compared to 'background' values. In contrast, an enhancement of the near-infrared diffuse component by 66%, was observed, while in visible and ultraviolet bands the relative increases reached 54% and 21% respectively. Experimental total Rayleigh-corrected and spectral aerosol optical depths were retrieved, representing differences in polluted air over the Athens atmosphere. The diffuse component accounts for more than 80% of the total radiation field under high polluted atmosphere. The observed differences of solar radiation between the Athens center and at a nearby suburban site are a manifestation of contrasting air properties provided mainly by automotive traffic. (Author)

  11. Solar energy and the abatement of atmospheric emissions

    International Nuclear Information System (INIS)

    Mirasgedis, S.; Diakoulaki, D.; Assimacopoulos, D.

    1996-01-01

    In spite of the fact that solar energy is a ''clean'' energy form, gaseous pollutants are emitted during the manufacturing of the systems necessary for its utilisation. An attempt is made in this paper to estimate the level of atmospheric pollutants emitted during the successive stages which make up the manufacture process for solar water heating (SWH) systems, and to evaluate these results in comparison with the respective pollutant emission levels attributed to the generation of electricity in Greece's conventional power plants. As energy consumption is recognised as the main source of atmospheric pollution, a Life Cycle Analysis (LCA) method was applied, focusing on the most energy-consuming stages of the SWH system production process. The conclusions of the analysis indicate that the emissions of gaseous pollutants associated with the utilisation of solar energy are considerably lower than those caused by the production of electricity in conventional systems, thereby substantiating that solar energy utilisation can make a notable contribution to the abatement of atmospheric pollution. (author)

  12. Annual atmospheric mercury species in downtown Toronto, Canada.

    Science.gov (United States)

    Song, Xinjie; Cheng, Irene; Lu, Julia

    2009-03-01

    Real-time concentrations of atmospheric gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and mercury associated with particles having sizes RGM were 4.5 +/- 3.1 ng m(-3) (99.2%), 21.5 +/- 16.4 pg m(-3) (0.5%) and 14.2 +/- 13.2 pg m(-3) (0.3%), respectively. The concentrations for all the measured Hg species were highly variable throughout the year and were lower in winter than in the other three seasons. The maximum concentrations of Hg species were observed in June and were a result of the high number of Hg spikes (using [GEM] >10 ng m(-3) as an indicator) that occurred in the month. Nighttime (between 9pm-6am) concentrations of Hg species were higher than those of daytime. The results revealed: (1) an urban area is a continuous source of Hg species that have the potential to pose impacts on local, regional and global scales; (2) local/regional anthropogenic sources contributed significantly to the levels and the distributions of the Hg species in the urban atmosphere. More studies are needed to identify and quantify the anthropogenic sources of Hg and the Hg species emitted from these sources; (3) surface emission and photochemical reactions (including the reactions involving ozone) did not have significant influence on the levels of Hg species and their distribution in the urban atmosphere.

  13. Metrological traceability of carbon dioxide measurements in atmosphere and seawater

    International Nuclear Information System (INIS)

    Rolle, F; Pessana, E; Sega, M

    2017-01-01

    The accurate determination of gaseous pollutants is fundamental for the monitoring of the trends of these analytes in the environment and the application of the metrological concepts to this field is necessary to assure the reliability of the measurement results. In this work, an overview of the activity carried out at Istituto Nazionale di Ricerca Metrologica to establish the metrological traceability of the measurements of gaseous atmospheric pollutants, in particular of carbon dioxide (CO 2 ), is presented. Two primary methods, the gravimetry and the dynamic dilution, are used for the preparation of reference standards for composition which can be used to calibrate sensors and analytical instrumentation. At present, research is carried out to lower the measurement uncertainties of the primary gas mixtures and to extend their application to the oceanic field. The reason of such investigation is due to the evidence of the changes occurring in seawater carbonate chemistry, connected to the rising level of CO 2 in the atmosphere. The well established activity to assure the metrological traceability of CO 2 in the atmosphere will be applied to the determination of CO 2 in seawater, by developing suitable reference materials for calibration and control of the sensors during their routine use. (paper)

  14. The deposition of radioiodine onto rice plant from atmosphere

    International Nuclear Information System (INIS)

    Uchida, Shigeo; Muramatsu, Yasuyuki; Yoshida, Satoshi; Sumiya, Misako; Ohmomo, Yoichiro.

    1994-01-01

    Radiation dose estimations are usually made with the aid of assessment models in which model parameters such as the transfer factors of radionuclides from one environmental compartment to another are involved. In simple models the parameters are often described as the concentration ratio of a radionuclide between two compartments, when the system is under equilibrium condition. In this paper, the authors introduce the values of the parameters of radioiodine obtained by tracer experiments. Laboratory experiments on the transfer parameters of radionuclides from the atmosphere to rice plant were carried out in the atmosphere-to-crops system (deposition pathway). It is known that the typical chemical species of gaseous iodine in the atmosphere are elemental iodine (I 2 ) and methyliodide (CH 3 I). The deposition characteristics of both chemical species of gaseous iodine to rice grains were obtained. Mass normalized deposition velocity (V D ) and grain number normalized deposition velocity (V S ) of gaseous elemental iodine (I 2 ) and also methyliodide (CH 3 I) on unhulled rice were measured. Both V D and V S of methyliodide were about one percent of those of elemental iodine. Distribution pattern of methyliodide between unhulled rice and brown rice was significantly lower than that of elemental one. For wet deposition, we investigated the retention of radioiodines (iodide [I - ] and iodate [IO 3 - ] on rice grains and their translocation from the surface of the grains to brown rice. Though the ears were dipped into the solution containing 125 I - or 125 IO 3 - more than 15 min., both iodine species in the solutions were hardly taken up to the rice grains. The transfer rates of iodide and iodate, which are defined as 'the amount of the iodine in brown rice' divided by 'the amount of iodide in unhulled rice' were about 0.015 and 0.04, respectively. The rates were not changed with time after the radioiodine application. (author)

  15. Portable and Disposable Paper-Based Fluorescent Sensor for In Situ Gaseous Hydrogen Sulfide Determination in Near Real-Time.

    Science.gov (United States)

    Petruci, João Flávio da Silveira; Cardoso, Arnaldo Alves

    2016-12-06

    Hydrogen sulfide is found in many environments including sewage systems, petroleum extraction platforms, kraft paper mills, and exhaled breath, but its determination at ppb levels remains a challenge within the analytical chemistry field. Off-line methods for analysis of gaseous reduced sulfur compounds can suffer from a variety of biases associated with high reactivity, sorptive losses, and atmospheric oxidative reactions. Here, we present a portable, online, and disposable gas sensor platform for the in situ determination of gaseous hydrogen sulfide, employing a 470 nm light emitting diode (LED) and a microfiber optic USB spectrometer. A sensing layer was created by impregnating 2.5 μL (0.285 nmol) of fluorescein mercury acetate (FMA) onto the surface of a micropaper analytical device with dimensions of 5 × 5 mm, which was then positioned in the optical detection system. The quantitative determination of H 2 S was based on the quenching of fluorescence intensity after direct selective reaction between the gas and FMA. This approach enabled linear calibration within the range 17-67 ppb of H 2 S, with a limit of detection of 3 ppb. The response time of the sensor was within 60 s, and the repeatability was 6.5% (RSD). The sensor was employed to monitor H 2 S released from a mini-scale wastewater treatment tank in a research laboratory. The appropriate integration of optoelectronic and mechanical devices, including LED, photodiode, pumps, and electronic boards, can be used to produce simple, fully automated portable sensors for the in situ determination of H 2 S in a variety of environments.

  16. Long-range transport of gaseous 131I and other radionuclides from Fukushima accident to Southern Poland

    Science.gov (United States)

    Mietelski, Jerzy W.; Kierepko, Renata; Brudecki, Kamil; Janowski, Paweł; Kleszcz, Krzysztof; Tomankiewicz, Ewa

    2014-07-01

    A serious accident at Fukushima Dai-Ichi NPP triggered radioactive emission to the atmosphere on 12 March 2011. The results of gamma spectrometric measurements of both gaseous and aerosol fraction of the air, collected in Krakow over the period from March 21 till the end of May 2011, as well as wet and dry deposition recorded from March till the end of October 2011, are presented in this paper. Krakow happened to be the first Polish location where radioactive isotopes characteristic for reactor releases, such as 131I, 132I, 129mTe, 132Te, 134Cs, 136Cs, and 137Cs, were detected. The maximum activity for aerosols equal to (5.73 ± 0.35) mBq/m3, (0.461 ± 0.041) mBq/m3 and (0.436 ± 0.038) mBq/m3 for 131I, 134Cs and 137Cs, respectively, was recorded for March 29, 2011. The data on the fallout are also given. The results of the radiochemical analysis of aerosol samples showed no traces of plutonium or americium isotopes associated with the disaster to be detected. The results of air activity concentration from Fukushima accident observed in Central Europe, Poland, in comparison to those of Chernobyl accident observed in Japan are presented and discussed. The comparison has revealed a discrepancy in the recognized relative scale of both accidents, and important difference in long distance transport of contamination, to exist. An attempt to explain the variation in the activity ratios between the aerosol fraction for 131I and 137Cs as resulting from exchange between the gaseous and aerosol fractions of 131I while the contamination had been propagating, is made.

  17. Liquid and Gaseous Waste Operations Department annual operating report, CY 1995

    International Nuclear Information System (INIS)

    Maddox, J.J.; Scott, C.B.

    1996-03-01

    This report describes the operating activities, upgrade activities, maintenance, and other activities regarding liquid and gaseous low level radioactive waste management at the Oak Ridge National Laboratory. Miscellaneous activities include training, audits, tours, and environmental restoration support

  18. Experimental and Detailed Numerical Studies of Fundamental Flame Properties of Gaseous and Liquid Fuels

    National Research Council Canada - National Science Library

    Egolfopoulos, Fokion N

    2006-01-01

    .... The experimental data are important for a number of reasons. First, they constitute a basis for partially validating the combustion chemistry of a large number of fuels ranging from hydrogen to gaseous and liquid hydrocarbons and alcohols...

  19. The role of multidimensional instabilities in direct initiation of gaseous detonations in free space

    KAUST Repository

    Shen, Hua; Parsani, Matteo

    2017-01-01

    We numerically investigate the direct initiation of detonations driven by the propagation of a blast wave into a unconfined gaseous combustible mixture to study the role played by multidimensional instabilities in direct initiation of stable

  20. Salient features in the preparation of gaseous tritium filled luminous light sources

    International Nuclear Information System (INIS)

    Mathew, K.M.; Ravi, S.; Subramanian, T.K.; Ananthakrishnan, M.

    2003-01-01

    Beta radiation emanating from gaseous tritium in close proximity with copper activated zinc sulphide phosphor provides self sustained light sources and these sources are used for nocturnal illumination of liquid crystal display in digital watches and clocks, product advertisements, exit signs etc. We report herein the preparation of low specific radioactivity gaseous tritium (29.5 Ci/m mole; 1.09 TBq/m mole) filled light sources and its effect on light output. (author)