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  • Electronic Resource  (10)
  • 1980-1984  (7)
  • 1935-1939  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 32 (1984), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
    Notes: Zero-offset-source VSP surveys provide information about the subsurface only within the Fresnel zone centered at the well. Offsetting the source location moves the reflection zones away from the well thus providing lateral cover.Conventional processing of this type of data gives rise to a distorted image of the subsurface. Using a simple ray-tracing scheme, this image may be reconstructed into the more familiar coordinate system of the surface seismic section. This simple data-independent mapping is based on the assumption of horizontal layering and requires a vertical velocity profile.The technique of placing the source away from the borehole was first applied to the single-offset-source VSP survey. However, data from any survey geometry (such as deviated well with rig source, walkaway VSP, etc.) can be mapped to the coordinate system defined by the appropriate seismic section.To obtain the best results from this type of survey the target area must be defined and simple modeling techniques used to optimize the source location(s). These pre-survey modeling methods may also be used to anticipate—and hence avoid a number of problem areas which experience has highlighted.The data from any VSP survey is the result of a realizable experiment and as such obeys the wave equation. This implies that the wave equation may be used to migrate the data to its true subsurface location. Theoretically, such a process is more secure than ray-tracing techniques, although its practice presents many difficulties.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 37 (1981), S. 442-443 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The purple pigment of the gorgonianParamuricea chamaeleon has been isolated and identified as linderazulene (I).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 275 (1983), S. 365-370 
    ISSN: 1432-069X
    Keywords: 5,8-Dihydroxyflavone (primetin) ; Contact allergy ; Sensitizing experiments ; Primetinquinone ; Flavones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 5,8-Dihydroxyflavone (primetin) has been shown to be the sensitizer in Primula mistassinica Michaux and probably the source of allergic contact dermatitis in four milkers. Its sensitizing properties as determined in guinea-pigs, are strong. As far as is known this is the first experimental demonstration of the sensitizing potency of a flavone. Presumably the flavone, with its uncommon 5,8-arrangement of hydroxy groups, is oxidized in the skin to the corresponding quinone (primetinquinone). Quinone was prepared from primetin and used for experimental sensitization of guinea-pigs. It also revealed strong sensitizing properties. Cross-reactions were obtained not only with the synthetic quinone in the flavone-sensitive animals but also with primetin in primetinquinone-sensitive guineapigs. Preliminary sensitization tests with other flavones have demonstrated that the whole group of flavonoid components should be taken into consideration as potential sensitizers.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A process for the treatment of animal wastes and the production of protein is under development at the University of Queensland. Animal wastes are fermented to produce organic acids which are then utilised by a pellicle-forming yeast, Candida ingens. This is harvested by skimming. The process removes carbon and minerals, particularly calcium and phosphorus, from the medium and Salmonella and Escherichia coli in the wastes are killed. The dry matter yield of C. ingens and its utilisation of volatile fatty acids (VFA) and oxygen were studied in order to improve the understanding of the process. When C. ingens was grown on a synthetic medium containing seven VFA and salts there was a significant increase in yield when the medium was reduced with sodium sulphide or cysteine hydrochloride. The VFA were utilised continuously over 24 h. After inoculation there was a shorter lag phase for the straight chain acids than for propionic and the branched chain acids, isobutyric, and isovaleric, but all acids showed a similar rate of utilisation of carbon during the period of most rapid utilisation. Candida ingens is an aerobe which, when growing as a pellicle, requires a reduced medium analogous to that used by anaerobes. It was concluded that pellicle growth on a medium containing several VFA takes place by utilising oxygen from the gaseous phase above, while all other nutrients are obtained from the reduced liquid phase below.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 110 (1937), S. 70-75 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 112 (1938), S. 223-224 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-5036
    Keywords: Clay ; Drought ; Sandy loam ; Waterlogging ; Winter barley ; Winter wheat ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of winter waterlogging and a subsequent drought on the growth of winter barley and winter wheat have been examined. We used lysimeters containing soil monoliths with facilities to control the water table and a mobile shelter to control rainfall. Winter wheat was grown on a clay and on a sandy loam, but winter barley only on the clay soil. Lysimeters were either freely-drained during the winter or waterlogged with the water table 10 cm below the soil surface from 2 December until 31 March (that could occur by rainfall with a return period of 2 to 3 years). The lysimeters then were either irrigated so that the soil moisture deficit did not exceed 84 mm, or subjected to drought by limiting rainfall (equivalent to a 1 in 10 dry year in the driest area of England) so that the deficits reached maximum values of 150 mm in the clay and 159 mm in the sandy loam by harvest. Winter waterlogging restricted tillering and restricted the number of ears for all crops; grain yield of the winter barley was decreased by 219 g/m2 (30%), and that of winter wheat by 170 g/m2 (24%) and 153 g/m2 (21% on the clay and sandy loam respectively. The drought treatment reduced the straw weight of winter barley by 75 g/m2 (12%) but did not significantly depress the grain yield. For winter wheat on the clay, where the soil was freely-drained during the winter, drought depressed total shoot weight by 344 g/m2 (17%) and grain weight by 137 g/m2 (17%), but after winter waterlogging, drought did not further depress total or grain weight. In contrast, the winter wheat on the sandy loam was not significantly affected by drought. From these results, which are discussed in relation to other experiments in the United Kingdom, it seems that winter waterlogging is likely to cause more variation in the yield of winter barley and winter wheat than drought.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    International journal of fracture 26 (1984), S. 99-112 
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résumé En utilisant des éprouvettes de traction entaillées axisymétriques soumises à état plan de déformation, analysées par éléments finis élasto-plastiques, on a pu élaborer une gamme importante d'états de tension. En combinant les observations de lacunes de section métallographique avec l'histoire des déformations calculées et des équations de croissance d'une cavité, on a déterminé les conditions locales qui président à la croissance de cavité et à la résistance de l'interface particule-matrice. Ces calculs montrent que l'apparition de cavités est un évènement statistique pour lequel la contrainte radiale à l'interface particule-matrice a pû être déterminé. Des calculs subséquents fournissent les conditions locales qui conduisent à la -coalescence de lacunes dans un matériau standard et pour des conditions d'inhomogénéité statistiquement réparties. La statistique de distribution des inclusions détermine l'échelle au delà de laquelle une coalescence de porosités peut se produire et crée un défaut assimilable `a une fissure.
    Notes: Abstract A wide range of stress states has been generated using axisymmetric and plane strain notched tensile specimens which have been analysed by elastic-plastic finite element analysis. Observations of voids on metallographic sections have been combined with calculated deformation histories and the hole growth equations to determine the local conditions for hole nucleation and the strength of the particle-matrix interface. These calculations show that nucleation is a statistical event for which the radial stress at the particle/matrix interface has been determined. Subsequent calculations give the local conditions at void coalescence in the average material and in statistical inhomogeneities. The statistics of the inclusion distribution determine the size scale over which void coalescence must occur in order to create a crack-like defect.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    International journal of fracture 24 (1984), S. 209-228 
    ISSN: 1573-2673
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Résumé A une échelle microscopique, une rupture démarre souvent au voisinage d'inclusions dans une matrice déformée où les conditions de contrainte et de déformation locales peuvent conduire soit à une rupture de l'interface inclusion/matrice ou de la particule elle-même. Des solutions analytiques sont disponibles pour déterminer les champs locaux de contrainte et de déformation au voisinage d'une inclusion élastique dans une matrice élastiquement déformée, mais pour des déformations plastiques, il est nécessaire de recourir à des analyses numériques. On présente ici une solution numérique applicable à une inclusion élastique sphérique dans une matrice élasto-plastique, en se concentrant largement sur l'interface particule/matrice qui est en cause dans la rupture ductile. Des solutions sont également présentées pour des inclusions rigides et élastiques situées dans des matrices en matériau durcissable ou non durcissable.
    Notes: Abstract At a micro-sclae, fracture often starts in the vicinity of inclusions in a deforming matrix where the local stress and strain conditions may lead to either failure of the inclusion/matrix interface or of the particle itself. Analytic solutions are available for the local stress and strain fields near an elastic inclusion in an elastically deforming matrix but for plastic deformation it is necessary to resort to numerical analyses. Here a numerical solution is presented for a spherical elastic inclusion in an elastic/plastic matrix, concentrating largely on the particle/matrix interface which is of relevance to ductile fracture. Solutions are also presented for rigid and elastic inclusions in hardening and non-hardening matrices.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 101 (1935), S. 56-57 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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