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  • 1
    Electronic Resource
    Electronic Resource
    Leaf-root interaction in the uptake of ammonia by Zostera marina (1982)
    Springer
    Marine biology 72 (1982), S. 109-112 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of ammonia uptake by one organ on the uptake of that nutrient by another organ was determined for the seagrass Zostera marina L. under laboratory conditions. Leafy shoots with roots attached were incubated in two-compartment chambers, with the roots in one compartment and the leaves in the other. Rates of ammonia uptake were compared when roots and leaves were supplied with ammonia separately and simultaneously. Root uptake of ammonia had no influence on the rate of ammonia uptake by leaves. However, leaf uptake of ammonia caused a 77% decrease in the maximum rate of ammonia uptake by roots. The Ks values for ammonia uptake by leaves and roots were 9.2 and 104 μM respectively, showing that leaves had a greater affinity for ammonia than roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396910
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Interaction of leaves and roots of Ruppia maritima in the uptake of phosphate, ammonia and nitrate (1984)
    Springer
    Marine biology 83 (1984), S. 61-67 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leafy shoots of Ruppia maritima were incubated in two-compartment chambers, with the roots in one compartment and the leaves in the other. Rates of phosphate and ammonia uptake were compared when roots and leaves were supplied with these nutrients separately and simultaneously. Uptake of phosphate and ammonia by leaves was reduced when these nutrients were supplied to the roots, but uptake by roots was not affected by the availability of these nutrients to leaves. This response suggested root-to-shoot translocation predominated. Vmax for leaf uptake of phosphate was decreased by 31% when roots were supplied with phosphate simultaneously. Leaf uptake of ammonia was not affected by the availability of ammonia to roots unless the plants were starved for nitrogen. Vmax for plants starved for nitrogen was two times greater than for unstarved plants. When roots and leaves of starved plants were exposed simultaneously to ammonia, Vmax for ammonia uptake by leaves did not change but Ks increased by 97% to a value similar to that for unstarved plants. Ammonia supplied to leaves or roots inhibited nitrate uptake by leaves by an average of 52%. Ammonia supplied to leaves, however, had no influence on the rate of nitrate uptake by roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393086
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    The Use of Fibre Optic Sensors for Damage Detection and Location in Structural Materials (2004)
    s.l. ; Stafa-Zurich, Switzerland
    Applied mechanics and materials Vol. 1-2 (Sept. 2004), p. 191-196 
    Details
    ISSN: 1662-7482
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The measurement of changes in the properties of ultrasonic Lamb waves propagating through structural material has frequently been proposed as a method for the detection of damage. In this paper we describe work that uses optical fibre sensors to detect the Lamb waves and show that the directional properties of these sensors allow us to not only detect damage, but also to locate it. We look at two types of optical fibre sensor, a polarimetric sensor and the fibre Bragg grating.The polarimetric sensor measures the change in birefringence of a fibre caused by the pressure wave of the ultrasound acting upon it. This is an integrated sensor since the fibre length bonded to the sample needs to be greater than the ultrasonic wavelength in order to obtain the required sensitivity. The maximum sensitivity of this sensor is when the fibre is positioned normal to the direction of wave propagation. Fibre Bragg gratings are essentially point sensors since the gratinglength needs to be a fraction of the ultrasound wavelength to obtain maximum sensitivity. Ultrasound is detected mainly through the in-plane strain it produces and maximum sensitivity is therefore produced when the grating is aligned parallel to the direction of wave propagation. Holes drilled into sample plates can be detected using both type of sensor by examining the changes in either the transmitted Lamb wave or through detection of the reflections produced by the hole. The sensitivity of the technique is shown to be determined by the relative positions of the acoustic source, the hole and the sensor. If we use fibre Bragg gratings in a rosette configuration (i.e. 3 gratings forming an equilateral triangle) then the direction of the Lamb wave can be determined using the directional sensitivities of the gratings. Using two such rosettes allows us to calculate the source of the wave from the intersection of two of these directions. If the source of the wave is the hole (which acts as a passive source), then the location of that hole can be determined
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/38/transtech_doi~10.4028%252Fwww.scientific.net%252FAMM.1-2.191.pdf
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  • 4
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    Unknown
    A perennial philosophy perspective on Richard Rorty's neo-pragmatism (1985)
    The Hague : Periodicals Archive Online (PAO)
    International journal for the philosophy of religion. 17:1/2 (1985) 41 
    Details
    ISSN: 0020-7047
    Topics: Philosophy , Theology and Religious Studies
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:d538-1985-017-01-000004
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  • 5
    Electronic Resource
    Electronic Resource
    Improvement of magnetic properties of electrical steels using a surface diffusion technique (1983)
    Springer
    Journal of materials science 18 (1983), S. 1657-1665 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The preceding paper described the general process by which the magnetic properties of electrical steels can be improved by a surface diffusion technique. This paper describes detailed effects of adding aluminium or silicon to non-oriented and grain-oriented silicon-iron. The addition of silicon proved more difficult and surface porosity tended to increase the power loss of grain-oriented steel whereas a paste containing aluminium powder was effective on all the materials although it was found that the powder size was critical. A reduction of 10% at 1.5 T in well oriented silicon-iron was achieved using the aluminium powder and an improvement in stress sensitivity of the magnetic properties also resulted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542060
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  • 6
    Electronic Resource
    Electronic Resource
    Assessment of a novel method of improving the characteristics of electrical steels by a surface diffusion technique (1983)
    Springer
    Journal of materials science 18 (1983), S. 1650-1656 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A method of adding either aluminium or silicon to electrical steel sheet from a coating applied to its surfaces is described. This is done in order to improve the a.c. magnetic properties of the material through the setting up of a controlled resistivity gradient through the thickness of the material. A paste containing the chosen element in powder form mixed with sodium silicate solution is applied to the steel, which is then heated to such a temperature as permits diffusion of the element into it. Suitable control of the amount and distribution of the element can yield reductions in iron loss, magnetostriction and stress sensitivity of the material. In this paper the controlling parameters are discussed in detail; a subsequent paper will describe a series of experiments carried out on a range of materials using both silicon and aluminium pastes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542059
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    Paper (German National Licenses)
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