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Emission of nitrogen oxides (NO x ) from a flooded soil fertilized with urea: Relation to other nitrogen loss processes (1987)

Galbally, I. E. ; Freney, J. R. ; Muirhead, W. A. ; [et al.]

Springer

Journal of atmospheric chemistry 5 (1987), S. 343-365

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ISSN: 1573-0662

Keywords: Nitrogen oxides ; nitric oxide ; biological production ; surface fluxes ; emission ; uptake ; rice paddy ; nitrogen fertilizer ; urea ; ammonia ; nitrification ; denitrification

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology , Geosciences

Notes: Abstract Emissions of nitric oxide and other odd nitrogen oxides (NO x ) from a flooded rice field were studied after urea had been broadcast into the floodwater. The NO x flux from the fertilized area was very low (0.2×10-9 g N m-2 s-1) for the first few days after application of urea and was high (0.95×10-9 g N m-2 s-1) in the subsequent period when significant nitrite and nitrate were present in the floodwater. At night, little if any NO x was exhaled but ambient NO2 was absorbed by the floodwater. An uptake velocity for NO2 of 3×10-4 m s-1 was measured during one night. Maximum NO x losses were observed near 1300 h when temperature and solar ultraviolet light were maximum. While the amounts of nitrogen oxides emitted are of little agronomic importance (∼2×10-3 per cent of the fertilizer nitrogen was lost as NO x during the 10-day study period), they may well be of significance as a source for some gas reactions in the atmosphere and for the global nitrogen cycle. Of the fertilizer nitrogen applied (as urea) approximately 30% was lost to the atmosphere by NH3 volatilization, 15% by denitrification, presumably as N2, and the remainder, less minor losses of NO and N2O, remained in the plant/soil/water system.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00114111

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Novel fused silica capillary columns: Surface modification through controlled doping of the preform-tube (1988)

Anthony, L. J. ; Soto, L. ; Heffner, S. A. ; [et al.]

Weinheim : Wiley-Blackwell

Journal of High Resolution Chromatography 11 (1988), S. 395-400

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ISSN: 0935-6304

Keywords: Gas chromatography (GC) ; Fused silica ; Column technology ; Surface modification ; Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: A method has been developed for fabricating fused silica capillary columns which have specific surface properties but still retain the excellent strength, flexibility, and resilience of pure fused silica. By using the Modified Chemical Vapor Deposition process (MCVD), typically used for the production of optical fiber lightguides, inorganic dopants such as Al, Nd, Ge, and P can be introduced into the preform-tube by MCVD. Doped columns have a wide range of specific surface properties, and columns with undoped fused silica prepared by MCVD are more chemically inert and less acidic than columns prepared by conventional methods. This paper describes the method for fabricating capillaries and the initial studies to characterize them.

Additional Material: 8 Ill.