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  • 1
    Electronic Resource
    Electronic Resource
    Mathematical models for mixing in deep-jet bioreactors: Calculation of parameters (1991)
    Springer
    Bioprocess and biosystems engineering 7 (1991), S. 177-182 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The macroscopic mathematical model based on compartments with ideal mixing zones and tanks-in series was evaluated. Based on the experimental data obtained in a 300 dm3 pilot reactor and the dependence of mixing time on the volume of liquid phase, we have found mathematical relations between the ratio of vessel diameter to liquid level, adjustable parameters of model and the mixing time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387414
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  • 2
    Electronic Resource
    Electronic Resource
    Mathematical models for mixing in deep jet bioreactors: analysis (1991)
    Springer
    Bioprocess and biosystems engineering 7 (1991), S. 171-176 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A mathematical model for single and multi step deep-jet bioreactors is presented. A stagewise approach based on macroscopic mechanistic model which divides the reactor into compartments with good quality of mixing and plug flow regions (macromixer), was used. For the mathematical representation of this model a system of differential equations, describing the concentration of tracer in structural elements based on mass balance, and the Runge-Kutta-Fehlberg numerical method of integration, was applied. The mixing time in a 300 dm3 tank was determined by conductivity method with NaCl as tracer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387413
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    REUSE OF POWER PLANT COOLING WATER FOR IRRIGATION (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 16 (1980), S. 0 
    Details
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Current water quality policies in California require disposal of saline blowdown waters from power plants in sealed evaporation ponds to avoid degradation of ground waters. This policy highlights the conflict between increased energy demands, increasing scarcity of water, and environmental priorities. Saline blowdown waters can be used for the irrigation of salt tolerant crops, albeit with some reduction in yields. The results of experiments intended to specify these yield reductions are reported. If such irrigation is carefully managed, the soil profile can be used to store residual salts and ground water degradation will be avoided, provided that irrigation ceases before the salts are leached to the ground water. An analysis of discharge below a carefully managed irrigation project shows that the downward movement of salts below the root zone is no worse than with conventional methods of disposal. Thus, irrigation reuse with blowdown water is shown to be a viable means of saline water disposal while maintaining existing standards of ground water quality protection. Further analysis demonstrates the economic feasibility of such irrigation reuse by showing that it is significantly less costly than the evaporation pond alternative.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1752-1688.1980.tb02495.x
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    A proposal for reclamation by dilution of irrigation water (1980)
    Springer
    Irrigation science 1 (1980), S. 161-168 
    Details
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A proposal is developed for reclamation of a soil which has become salinized from irrigation with saline water. The procedure permits continued irrigation after dilution of the saline irrigation water with higher quality water, which achieves partial reclamation without taking the land out of production, and without creating a large flux of drainage. Model calculations using a salt transport-chemical equilibrium model are performed for the case of a saline irrigation water derived from power plant cooling water residual (EC=4.2 mmho/cm), which is diluted by a high quality well water (EC=0.5 mmho/cm) to produce a water which is alternated with the saline water in cycles of two years. Soil salinity and drainage salt loads resulting under this system are compared with the simulated results of a more traditional method of salt leaching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270880
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Comparison of methods used to estimate evapotranspiration for leaching control (1983)
    Springer
    Irrigation science 4 (1983), S. 59-69 
    Details
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In this study six different methods for controlling leaching by predicting crop water use were compared over a full season with sorghum in southern California. The standard for comparison was a 1.8 m × 1.8 m lysimeter located in the center of the 1.4 ha field. The Penman equation was the most successful of the methods which were tested with predicted evapotranspiration deviating± 15% on a weekly basis from measured lysimeter values. The other methods were less successful with errors ranging from ± 23 to 48%. The influence of sprinkler system application uniformity on leaching uniformity was examined. Although the coefficient of uniformity of the sprinkler system was very high, the portions of the total area receiving the least amount of water were concentrated in a single area which, coupled with the error involved in predicting evapotranspiration, seriously limits the minimum practical leaching fraction that should be attempted if maximum crop yields are desired.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00285557
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Application of automated flow and salinity control to dilution of saline irrigation water (1985)
    Springer
    Irrigation science 6 (1985), S. 179-190 
    Details
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The utility of a saline water source for irrigation might, in many cases, be greatly increased if it could be diluted by mixing it with a higher quality source of water prior to field application. This paper discusses a number of options for achieving such a dilution subject to imposed constraints. Firstly, we derive and discuss the principles of achieving control of irrigation salinity level when waters of two different qualities and flow rates are used. Secondly, we formulate and discuss the dynamic performance of a prototype on a controlled dilution junction with and without water storage. Finally, we discuss the general problem of achieving simultaneous salinity and flow rate control, using dual feedback control sensors to compensate for variations both in salinity and in flow rate of the saline supply source in order to produce a desired salt concentration in the irrigation water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572666
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Response of sorghum to a water gradient and potassium variable (1986)
    Springer
    Plant and soil 93 (1986), S. 67-77 
    Details
    ISSN: 1573-5036
    Keywords: Deficit irrigation ; Evapotranspiration ; Leaching fraction ; Potassium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A field study utilizing a modified line-source sprinkler system was used to investigate the hydrologic balance of a sorghum crop subjected to water deficit stress. An additional objective was to evaluate the evapotranspiration-yield relationship and to determine if the water use efficiency could be improved through the addition of increased amounts of potassium. Sixteen lysimeters packed with a Greenfield sandy loam and planted to sorghum (Sorghum bicolor) were placed under a moisture gradient irrigation system. Four levels of potassium were used in the experiment (0, 100, 200 or 300 Kg/ha). The results indicated that when the leaching fraction was set at 0.15 near the source, the predicted leaching fraction would go to zero at 10 meters from the source. Although yield was related to evapotranspiration, a better fit to the yield data was obtained when a parameter that included an availability and deficit term was used. The relationship was not linear but instead was described by an exponential fit. This parameter was also highly sensitive to leaf water potential and diffusion resistance. Finally, water use efficiency increased with yield but showed no correlation with potassium application.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02377146
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    Paper (German National Licenses)
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