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  • 1
    Electronic Resource
    Electronic Resource
    The effect of increasing application rate of granular calcium ammonium nitrate on net nitrification in a laboratory study of grassland soils (1994)
    Springer
    Nutrient cycling in agroecosystems 40 (1994), S. 155-161 
    Details
    ISSN: 1573-0867
    Keywords: calcium ammonium nitrate ; granules ; nitrification ; rate of application
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil incubation studies were undertaken in controlled environment cabinets at 15°C to investigate the effect of increasing application rates of calcium ammonium nitrate (CAN) on net nitrification in two grassland soils. Granular CAN was applied to the surface of freshly collected, moist soil, at a rate equivalent to 0, 100, 200, 400, 800 and 1600µg NH 4 + -N and NO 3 - -N per gram of oven dry soil. In half the treatments finely ground CaCO3 was incorporated into the moist soil to raise the starting pH. Changes in soil mineral N and pH were measured at weekly intervals up to six-weeks. The most probable number (MPN) technique was used to enumerate the NH 4 + -N and NO 2 - -N oxidizers at the beginning and end of the incubation. At low rates of CAN application there was considerable NH 4 + -N oxidation to NO 3 - -N during the incubation of both soils. Lime stimulated this N transformation. At high application rates (i.e. 800 and 1600 ppm) there was little change in NH 4 + -N or NO 3 - -N on either soil during the 6 week incubation, in the presence or absence of lime. The rate of NO 3 - -N produced peaked at 5.6 and 3.8 mg NO 3 - -N kg−1 d−1 on soil 1 and 2 respectively, in the presence of lime. Above a level of 400 ppm CAN (equivalent to 38 kg N ha−1) the rate of NO 3 - -N produced decreased. The higher rate of net nitrification in soil 1 compared with soil 2 was probably due to a higher number of nitrifying bacteria. Although high rates of CAN decreased the nitrifying activity of both soils there was little difference between treatments in the actual numbers of NH 4 + -N and NO 2 - -N oxidizers determined by the MPN technique. The results showed that the rate of granular CAN applied to the soil surface can influence the local activity of nitrifying bacteria and subsequent N transformations. At application rates of CAN generally used agriculturally for grass production, it is likely that net nitrification of the NH 4 + -N in the fertilizer granule will be inhibited.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750101
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of urea pellet size and rate of application on ammonia volatilization and soil nitrogen dynamics (1991)
    Springer
    Nutrient cycling in agroecosystems 28 (1991), S. 163-172 
    Details
    ISSN: 1573-0867
    Keywords: Urea ; pellet size ; ammonia volatilization ; rate of application ; soil mineral nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two incubation experiments were conducted to investigate the effect of pellet size and rate of application on NH3 volatilization from surface-applied urea and on subsequent soil N transformations. In the first experiment fertilizer grade urea was applied as prills (1–2 mm diameter) or in four commercially available granule sizes with diameters of 2–3 mm, 3–4 mm, 5–6.3 mm and 6.3–8 mm. The five urea pellet sizes were applied to the soil surface of one soil at various N rates. In the second experiment four soils were used where the different pellet sizes were applied at a single application rate. The daily rates of NH3 loss were measured over 14 days in the laboratory under simulated spring conditions using ventilated enclosures. In the first experiment the highest total NH3 loss (Amax) was 17.4% of the urea N applied. Amax increased curvilinearly with rate of N applied up to the equivalent of 200 kg N ha−1. Higher rates of application did not lead to any further increase. Increasing the rate of N applied delayed the time to maximum rate of loss (Tmax), lowered soil NO 3 - —N levels and decreased total mineral N that could be recovered at the end of the incubation. The effect of pellet size on NH3 volatilization was dependent on soil type. On 2 soils studied pellet size had no significant effect whereas on other soils large granules could decrease or increase NH3 loss. However the effects were small. There was little difference on any of the soils between prills and the three smallest granule sizes on Amax or Tmax. The greatest effect was with the largest granules on soil 2. There was little difference between granule sizes on soil N transformations. However, N transformations from prills appeared to be different to the other pellet sizes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01049746
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of fluidization on catalytic cumene dealkylation (1956)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 2 (1956), S. 518-524 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper reports a direct experimental comparison of the cracking of cumene in a fluidized bed of silica-alumina catalyst with the same reaction in a fixed bed. The effects of fluidization on the kinetics of this reaction are interpreted in terms of an empirical approach using effectiveness factors and by a simplified mathematical model.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690020418
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  • 4
    Electronic Resource
    Electronic Resource
    The mixing of solid particles in a motionless mixer - a stochastic approach (1972)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 18 (1972), S. 984-989 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Markov chain model was used to model the axial mixing of solid particles in a motionless mixer having no moving parts. One step transition probabilities were determined experimentally for the model. Based on these transition probabilities, the model was able to predict spatial distribution of tracer particles up to seven steps of the Markov chain, which was equivalent to seven consecutive passes of the mixture through the mixer. Experimental results were in good agreement with those predicted from the Markov chain model.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690180515
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  • 5
    Electronic Resource
    Electronic Resource
    Nonlinear least squares analysis of catalytic rate models (1965)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 11 (1965), S. 1051-1057 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Conventional data generation and analysis procedures used to select a descriptive Hougen-Watson reaction rate model have been reviewed and some statistical objections to these conventional procedures have been presented. In an attempt to assess the practical importance of these objections, a recently published example was analyzed with both conventional techniques and nonlinear least squares procedures, which more closely conform to theoretical weighting requirements. Comparisons were made between the results of the conventional linear least squares analysis of isothermal data and those of nonlinear least squares analyses of both isothermal and nonisothermal data. It was found that the nonlinear least squares procedures were useful for a rational selection of an acceptable model and estimation of its parameters.General observations were made concerning good regions for further experimentation if a discrimination among rival models is desired. Additional well-designed experiments were found to be necessary to allow a reduction of the confidence region of the parameters of the Hougen-Watson models to an acceptable size.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690110618
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  • 6
    Electronic Resource
    Electronic Resource
    Correlation of bubble-cap fractionating-column plate efficiencies (1956)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 2 (1956), S. 18-25 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method of estimating the true conditions of operation of a bubble-cap tray is presented. Intermediate between the Murphree and the Lewis methods, which represent the extremes of actual operation, this method involves the use of a correlation to determine the degree of liquid mixing on the tray and the use of new relations between the Murphree vapor efficiency, the Lewis case I efficiency, and the true local efficiency. For the last, partial liquid mixing is taken into account.Data were obtained on an 18-in. O.D. three-tray bubble-cap tower containing ten 3-in. bubble caps a tray. Partial liquid mixing was correlated for changes in vapor and liquid rates, pressure, temperature, and weir height for the system ethylene dichloride-toluene.Efficiency data on acetone-water, ethanol-water, and ethylene dichloride-toluene showed the following effects: (1) low concentration of lwo boiler usually, but not always, resulted in low true local efficiencies, always with high Murphree efficiencies; (2) vapor velocity effects are more intimately connected with slot velocity than superficial velocity (and hence entrainment); (3) raising the pressure gives higher efficiencies; (4) an increase in liquid depth increases the true local efficiency but may have no effect on the Murphree efficiency.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690020105
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  • 7
    Electronic Resource
    Electronic Resource
    Obtaining precise parameter estimates for nonlinear catalytic rate models (1966)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 12 (1966), S. 5-10 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A method is reviewed which allows data points to be chosen in such a fashion that precise estimates of the parameters in nonlinear reaction rate models can be obtained. This method allows each future data point to be selected such that the confidence region of the estimated parameters is smaller with it than with any other possible data point within the region of experimentation. This procedure is applied for Hougen-Watson models with hypothetical experimental data which were generated with the guidance of an example from the current chemical engineering literature. It is found that, for the same number of data points, the parameters in the model can be estimated eighteen times more precisely by using this suggested experimental design than by another commonly used design. Confidence regions are presented for the parameters of the Hougen-Watson models with two types of designs.It is found that the positions of the data points in the well-designed experiments are more sensitive to the functional form of the model than to the current estimates of the magnitudes of the parameter values.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690120104
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetics of chemical processes, Michel Boudart, Prentice-Hall, Inc., Englewood Cliffs, N. J. (1968). 242 pages (1969)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 15 (1969), S. 320-320 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690150206
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  • 9
    Electronic Resource
    Electronic Resource
    Continuous-flow fast-atom bombardment on an external-ion-source Fourier transform ion cyclotron resonance mass spectrometer (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 249-251 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A continuous-flow sample interface for fast-atom bombardment has been developed for use on an external-ion-source Fourier transform ion-cyclotron resonance mass specstrometer. The new interface provides a quick and convenient means for sample introduction. A suppression of common glycerol matrix ions was observed when compared to static analysis. High mass resolution, exact mass measurements, and tandem mass spectrometry spectra were obtained on a sample of Gramicidin S.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290050509
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  • 10
    Electronic Resource
    Electronic Resource
    The analysis of water-soluble polymers by matrix-assisted laser desorption time-of-flight mass spectrometry (1992)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 27 (1992), S. 843-846 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210270717
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