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  • 1
    Electronic Resource
    Electronic Resource
    Ammonia volatilization from cattle slurry following surface application to grassland (1990)
    Springer
    Plant and soil 125 (1990), S. 119-128 
    Details
    ISSN: 1573-5036
    Keywords: ammonia ; application method ; application rate ; environment ; grassland ; nitrogen ; slurry ; volatilization ; wind speed
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three experiments were conducted to examine the influence of slurry application rate, wind speed and applying slurry in narrow bands on ammonia (NH3) volatilization from cattle slurry surface-applied to grassland. The experiments were conducted in the field using a system of small wind tunnels to measure NH3 loss. There was an inverse relationship between slurry application rate and the proportion of NH4 +-N volatilized. From slurry applied at 20, 40, 60, 80, 100 and 120 m3 ha-1, the respective proportions of NH4 +-N lost by NH3 volatization in 6 days were 60, 56, 49, 40, 44 and 44%. The negative relationship was most pronounced in the first 24 hours after application when 57–77% of the total loss for 6 days occurred. Wind speed had a positive effect on NH3 volatilization, although the effect was small in relation to the total loss; increasing the wind speed from 0.5 to 3.0 m s-1 increased the total 5 day loss by a factor of 0.29. The effect of wind speed was also most pronounced in the first 24 hours when much of the NH3 loss took place. The effect of reducing the surface area of the applied slurry was examined by comparing NH3 volatilization from slurry broadcast across plots with that applied in narrow bands. Although the rate of NH3 volatilization was considerably smaller from the banded application immediately after the slurry was applied, the difference between the treatments progressively narrowed until 2 days after application, after which a higher rate was maintained from the banded slurry. After 5 days the total loss from the banded application was 83% of that from broadcast slurry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010751
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  • 2
    Electronic Resource
    Electronic Resource
    Ammonia volatilization from cattle slurry following surface application to grassland (1990)
    Springer
    Plant and soil 125 (1990), S. 109-117 
    Details
    ISSN: 1573-5036
    Keywords: ammonia ; environment ; grassland ; mechanical separation ; nitrogen ; slurry ; volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three experiments were conducted using a system of small wind tunnels to measure ammonia (NH3) volatilization from cattle slurry after surface application to land. In each experiment slurry was applied at a rate equivalent to 80 m3 ha-1, providing the equivalent of approximately 100 kg NH4 +-N ha-1. The first experiment compared NH3 volatilization from the liquid fraction obtained by mechanical separation of slurry with that from unseparated slurry. The total NH3 loss over six days from unseparated and separated slurry were very similar, being 38 and 35% respectively of the NH4 +-N applied. For the first five hours, the rate of NH3 loss was higher from the unseparated slurry, thereafter it was consistently lower. In the second experiment, slurry was ponded in a tray to examine whether impeded infiltration or changes in the NH4 + concentration or overall pH of the slurry influenced the rapid decline in rate soon after application that is characteristic of NH3 volatilization from animal slurries applied to land. It appeared, however, that other factors such as resistance to diffusion within the slurry and/or at the slurry surface were mostly responsible for the rapid decline in rate. In the third experiment, in which NH3 volatilization was measured from slurry applied to grassland or bare soil, the total loss from slurry applied to grassland was approximately 1.5 times that from slurry applied to bare soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00010750
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  • 3
    Electronic Resource
    Electronic Resource
    Using calcium carbide with the acetylene inhibition technique to measure denitrification from a sprinkler irrigated vegetable crop (1996)
    Springer
    Plant and soil 179 (1996), S. 9-16 
    Details
    ISSN: 1573-5036
    Keywords: acetylene inhibition ; calcium carbide ; denitrification ; nitrogen ; vegetable production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The use of calcium carbide (CaC2) pellets as a source of acetylene (C2H2) for the C2H2 inhibition technique to measure denitrification in the field was examined in a sandy loam soil cropped to lettuce. CaC2 was used in combination with vented closed chambers. Three grams of 2–4 mm CaC2 pellets were inserted at 7 and 20 cm for raised beds, and 6 and 15 cm for furrows, in four holes located at right angles, 2.5 cm outside a 20 cm dia. chamber pushed 4 cm into the soil. Acetylene concentrations were determined in the centre of the chamber 1.0 and 4.0 hours after applying CaC2, in beds (two dates) and furrows (one date) at different depths to 20 and 15 cm, respectively, for beds and furrows. At soil matric potentials of ca. 0.01 and ca. 0.06 MPa, soil C2H2 concentrations were 〉1.0% (v/v) for all determinations. Weekly measurements of denitrification were made from a sprinkler irrigated lettuce crop for 8 weeks. Measurements were made 24 hours after irrigation and on one occasion 48 hours after. Measured mean rates of denitrification were generally 〈100 g N ha−1 d−1, much less than published data following furrow irrigation of vegetable crops in a nearby region. In another sandy loam soil at ca. 0.08 MPa, soil C2H2 concentrations were ≥2.0 % at 5 and 15 cm, 1.0 and 6.0 hours after adding CaC2. Using CaC2 to generate C2H2 in soil is a convenient approach for field measurements where the C2H2 inhibition technique is used with chambers to determine the nitrous oxide flux. In comparison with C2H2 supply via probe systems, CaC2 overcomes the requirements for cylinders of pressurised C2H2 gas and complex on-site plumbing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011637
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  • 4
    Electronic Resource
    Electronic Resource
    A circular dichroic investigation of the secondary structure of lectins (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 2107-2120 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The far-uv CD spectra of eight lectins are presented. These eight lectins, as well as others previously studied, are grouped into three classes according to their particular CD spectra. The eight lectins studied appeared to have secondary structure dominated by β-pleated sheet, which so far has been true of all lectins. An attempt was made to quantitate the three structural components (α-helix, β-pleated sheet, and aperiodic) in the lectins using the data for reference proteins given by Chen et al. [Biochemistry 13,3350 (1974)]. For lectins in two of the classes, this method proved excellent and values for the three components are given. However, for the third class of lectins, which includes most of the lectins as well as Concanavalin A, this method of analysis proved to be unsatisfactory. This inadequacy was due to two factors: (1) the reference proteins used by Chen and (2) the unusual CD spectra of these lectins manifested by considerable ellipticity above 225 nm in a region where there are no known peptide electronic transitions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360170906
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  • 5
    Electronic Resource
    Electronic Resource
    Basic dyeability and acid content of high-conversion polyacrylonitrile (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 3341-3351 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Previous data have shown that the basic dyeability of acrylic polymers increases at a given specific viscosity as the peroxydisulfate-to-bisulfite ratio, that is, the catalyst-toactivator (C/A) ratio, is increased. This study represents an effort to understand better the role of the initiator system on the basic dyeability, the acid group composition, and the chain composition of acrylic polymers by preparing model polymers with radioactive initiators. As the C/A ratio is increased, the molecular weight distribution broadens as measured by the M̄v/M̄n ratio, the latter obtained by osmometry. There is also a significant effect of both C/A ratio and molecular weight on the sulfate group content per molecule, but there is no effect of C/A ratio on the number of basic dye sites per molecule, the number of sulfonate groups per molecule, or the weak acid groups per molecule. These effects can be explained by invoking a chain transfer to activator reaction in addition to the usual method of chain termination by recombination. The basic dyeability is found to correlate with the number-average molecular weight and with the number of strong acid groups plus the nonchromophoric weak acid groups.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070161223
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  • 6
    Electronic Resource
    Electronic Resource
    GPC analysis of model compounds. I. Phenyl- and benzo-substituted aromatic compounds (1970)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 8 (1970), S. 1165-1190 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 36 compounds of known structure was used in a study to elucidate the mechanism of separation of gel-permeation chromatography (GPC). The various molecular dimensions were defined and measured for these compounds. The elution volume for these compounds was determined by GPC under specified and controlled conditions. The relationships between elution volume and molecular dimension were investigated using computer-based statistical analysis for the entire set of compounds and manual simultaneous equations for smaller sets of compounds. It was found that, as increasingly more molecular dimensions are considered, (1) the importance of the maximum molecular dimension Ap′ (the only dimension considered by many investigators) significantly decreases and (2) a significantly better prediction of the elution volume of these compounds could be made.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1970.150080511
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