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  • 1
    Electronic Resource
    Electronic Resource
    Neutron halo in lithium nuclei: A relativistic mean-field approach (1991)
    Springer
    The European physical journal 340 (1991), S. 119-124 
    Details
    ISSN: 1434-601X
    Keywords: 21.10.Ft ; 21.60.Jz ; 27.20.+ n
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Relativistic mean-field calculations have been carried out for Li isotopes using the non-linear Lagrangian parameter set NL2. Both spherically symmetric and axially deformed cases are considered. The binding energies, charge, neutron and matterrms radii, one and two neutron separation energies have been calculated. The results are discussed and compared with the available non-relativistic mean-field results, with special reference toneutron halo in the recent experimental observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01303823
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  • 2
    Electronic Resource
    Electronic Resource
    Compression properties of finite nuclei in a semi-classical relativistic approach (1991)
    Springer
    The European physical journal 339 (1991), S. 147-154 
    Details
    ISSN: 1434-601X
    Keywords: 11.10.Ef ; 21.10-k ; 21.60.-n
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Skyrme type potentials are known to lead — in the framework of the scaling model — to a finite-nucleus incompressibility valueK A where the volume coefficientK v equals roughly the negative surface coefficient Ks. This is found for Skyrme interactions with Kv between 200 and 360 MeV. In a semi-classical relativistic approach on the basis of theσ — ω model (linear as well as non-linear) using in addition local density approximations, we findK s to depend in particular on the surface energy coefficienta s , and not so much on the value ofK v . For a realistic value of as, both the linear and the non-linearσ — ω model (with NL1 parameter set) yield a ratio ¦K s K v ¦ of approximately 1. We discuss implications of this finding with a particular view on recent empirical results onK v andK s .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282944
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  • 3
    Electronic Resource
    Electronic Resource
    Continuous production of the lipopeptide biosurfactant of Bacillus licheniformis JF-2 (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 281-285 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Bacillus licheniformis JF-2 synthesizes a surf- actin-like lipopeptide that is the most effective biosurfactant known. In shake-flask cultures the biosurfactant is produced by actively growing cells (mid-linear phase), but subsequently it becomes rapidly internalized by the cells as soon as the culture enters the stationary phase. This deactivation phenomenon is a major hurdle in the efficient production of the biosurfactant. We have shown that the synthesis of the JF-2 lipopeptide is strongly dependent on O2 concentration with substantial production observed only in cultures grown under O2-limiting conditions. In continuous cultures the biosurfactant was produced only within a narrow window of low dilution rates. At a dilution rate of 0.12 h-1 and low dissolved O2, the biosurfactant concentration was maintained at 33 mg/l, which is virtually the same as the maximum concentration obtained in optimized batch fermentations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530050144
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  • 4
    Electronic Resource
    Electronic Resource
    Continuous production of the lipopeptide biosurfactant of Bacillus licheniformis JF-2 (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 281-285 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Bacillus licheniformis JF-2 synthesizes a surfactin-like lipopeptide that is the most effective biosurfactant known. In shake-flask cultures the biosurfactant is produced by actively growing cells (mid-linear phase), but subsequently it becomes rapidly internalized by the cells as soon as the culture enters the stationary phase. This deactivation phenomenon is a major hurdle in the efficient production of the biosurfactant. We have shown that the synthesis of the JF-2 lipopeptide is strongly dependent on O2 concentration with substantial production observed only in cultures grown under O2-limiting conditions. In continuous cultures the biosurfactant was produced only within a narrow window of low dilution rates. At a dilution rate of 0.12 h−1 and low dissolved O2, the biosurfactant concentration was maintained at 33 mg/l, which is virtually the same as the maximum concentration obtained in optimized batch fermentations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221219
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  • 5
    Electronic Resource
    Electronic Resource
    Alkylation of phenol with MTBE and other tert-butyl ethers: cation exchange resins as catalysts (1993)
    Springer
    Catalysis letters 19 (1993), S. 309-317 
    Details
    ISSN: 1572-879X
    Keywords: Cation exchange resin ; phenol ; methyl tert-butyl ether (MTBE) ; alkylation ; tert-butyl phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Alkylation of phenol was carried out using methyl tert-butyl ether, mono tert-butyl ether of mono ethylene glycol, tert-butanol and isobutylene in the presence of cation exchange resins, acid treated clay and para-toluene sulfonic acid as catalysts. The selectivity with respect to 2- and 4-tert-butyl phenol was studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00767072
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  • 6
    Electronic Resource
    Electronic Resource
    A study of the potential of hedgerow intercropping in semi-arid India using a two-way systematic design (1990)
    Springer
    Agroforestry systems 11 (1990), S. 243-258 
    Details
    ISSN: 1572-9680
    Keywords: Alley cropping ; fodder ; India ; intercrops ; Leucaena ; pigeonpea ; semi-arid tropics ; sorghum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The potential of hedgerow intecrropping with Leucaena leucocephala was explored on vertic Inceptisols over 4 years at ICRISAT Center, Patancheru, India. The study was conducted using a systematic layout involving different alley widths ranging from 1.35 to 4.95 m and with varying distances between hedge and crops. The alleys were cropped with alternate rows of sorghum and pigeonpea. Hedges composed double Leucaena hedgerows 60 cm apart were periodically harvested for fodder. Sole crops of all components and a sorghum/pigeonpea intercrop were included in all four replications of the study. Starting in the second year, Leucaena was progressively more competitive to annual crops, causing substantial yield reduction. Competition (primarily for moisture) was most severe in narrow alleys and was greatest on pigeonpea. The growth of Leucaena was not sufficient to compensate for reduced crop yields. Land equivalent ratios (LERs) calculated on the basis of grain yield of crops and Leucaena fodder yields showed that hedgerow intercropping (HI) was advantageous over sole crops only during the first two years using wide alleys, but disadvantegeous in the last two years. LERs calculated on the basis of total dry matter indicated only a small advantage for HI (13–17 percent) over sole crops in wider (〉4 m) alleys. Average returns per year from HI exceeded those of the most productive annual crop system (sorghum/pigeonpea intercropping) by 8 percent in 4.05 m alleys, and by 16 percent in 4.95 m alleys. Fodder production during the dry season was 40 percent of the annual total in these alley widths. Thus hedgerow intercropping at 4–5 m alley width is not very attractive for farmers in semi-arid India, which has 600–700 mm of annual rainfall. There is a need to examine the potential of HI in wider alleys. The merits and limitations of the systematic design are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045902
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  • 7
    Electronic Resource
    Electronic Resource
    A tree/crop interface design and its use for evaluating the potential of hedgerow intercropping (1991)
    Springer
    Agroforestry systems 13 (1991), S. 143-158 
    Details
    ISSN: 1572-9680
    Keywords: Tree-crop interface ; row orientation ; hedgerow intercropping ; alley cropping ; Leucaena ; sorghum ; sunflower ; experimental design ; semi-arid tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The paper describes a tree/crop interface (TCI) experiment designed to investigate the effects of row orientation using Leucaena leucocephala Lam. Each TCI plot consisted of a regularly pruned Leucaena hedge in the middle and 12 crop rows on either side. Eight such plots were arranged at 45° around a sole Leucaena plot with rows oriented in four compass directions viz., North-South, East-West, Northeast-Southwest and Northwest-Southeast. Results of four years from 1984 to 1987 did not show any effect of row orientation, and similarly, no effect was seen on crop rows due to their location on the windward or leeward side of the hedge. The TCI effect was positive on the first crop row in the first year because Leucaena grew slowly, but depressed the yield of the first 4 to 6 crop rows(1.8 to 2.7 m from hedge) in subsequent years. The negative effect of Leucaena was noted more on sunflower in a relatively dry year than on sorghum in other years. Results from the TCI plots were used to estimate the yield of five hedgerow intercropping (HI) systems with varying alley widths (2.7 to 9.9 m). Comparison with sole stands of Leucaena and crops indicated that HI was more productive particularly at close alley widths. For example, hedges spaced at 2.7 m and 3.6 m averaged 37% and 25% higher productivity than the respective sole stands; but this advantage may be an overestimation of the real potential. The relevance of TCI experiments for studying agroforestry systems, their merits and limitations, especially of the design employed in this study are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00140238
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  • 8
    Electronic Resource
    Electronic Resource
    Productivity of annual cropping and agroforestry systems on a shallow Alfisol in semi-arid India (1991)
    Springer
    Agroforestry systems 15 (1991), S. 51-63 
    Details
    ISSN: 1572-9680
    Keywords: perennials ; agroforestry ; alley cropping ; hedgerow intercropping ; Leucaena ; pearl millet ; pigeonpea ; castor ; semi-arid tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An experiment was conducted at ICRISAT Center, Patancheru, India from June 1984 to April 1988 on a shallow Alfisol to determine whether the productivity of annual crop systems can be improved by adding perennial species such as Leucaena leucocephala managed as hedgerows. Except in the first year, crop yields were suppressed by Leucaena due to competition for moisture. The severity of competition was high in years of low rainfall and on long-duration crops such as castor and pigeonpea. Based on total biomass, sole Leucaena was most productive; even on the basis of land productivity requiring both Leucaena fodder and annual crops, alley cropping had little or no advantage over block planting of both components. Application of hedge prunings as green manure or mulch on top of 60 kg N and 30 kg P 2 O 5ha−1 to annual crops did not show any benefit during the experimental period, characterized by below average rainfall. Indications are that (i) alley cropping was beneficial in terms of soil and water conservation with less runoff and soil loss with 3 m alleys than with 5.4 m alleys, and (ii) root pruning or deep ploughing might be effective in reducing moisture competition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00046278
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  • 9
    Electronic Resource
    Electronic Resource
    A LGA model for fluid flow in heterogeneous porous media (1994)
    Springer
    Transport in porous media 17 (1994), S. 1-17 
    Details
    ISSN: 1573-1634
    Keywords: Lattice gas model ; heterogeneous porous media ; fluid flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract A lattice gas automaton (LGA) model is proposed to simulate fluid flow in heterogeneous porous media. Permeability fields are created by distributing scatterers (solids, grains) within the fluid flow field. These scatterers act as obstacles to flow. The loss in momentum of the fluid is directly related to the permeability of the lattice gas model. It is shown that by varying the probability of occurrence of solid nodes, the permeability of the porous medium can be changed over several orders of magnitude. To simulate fluid flow in heterogeneous permeability fields, isotropic, anisotropic, random, and correlated permeability fields are generated. The lattice gas model developed here is then used to obtain the effective permeability as well as the local fluid flow field. The method presented here can be used to simulate fluid flow in arbitrarily complex heterogeneous porous media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00624047
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  • 10
    Electronic Resource
    Electronic Resource
    A LGA model for dispersion in heterogeneous porous media (1994)
    Springer
    Transport in porous media 17 (1994), S. 19-32 
    Details
    ISSN: 1573-1634
    Keywords: LGA model ; heterogeneous porous media ; miscible displacement ; dispersion ; tracer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The lattice gas automaton (LGA) model proposed in the previous paper is applied to the problem of simulating dispersion and mixing in heterogeneous porous media. We demonstrate here that tracer breakthrough profiles and longitudinal dispersion coefficients can be computed for heterogeneous porous media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00624048
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