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  • 1
    Electronic Resource
    Electronic Resource
    The effect of frequency and height of defoliation on the production and persistence of ‘Grasslands Matua’ prairie grass (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 44 (1989), S. 0 
    Details
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The performance of prairie grass (Bromus willdenowii Kunth) cv. Grasslands Matua was examined under mowing at five defoliation intervals (10, 20, 30, 40 and 50 d) and two defoliation heights (3 cm and 8 cm). Annual and seasonal production of both the total herbage and of Matua, and the proportion of Matua in the sward, increased with less frequent defoliation. To a lesser extent, increasing the height of defoliation increased dry matter yield. Matua tiller numbers were increased by less frequent defoliation and were greater under the 8 cm than the 3 cm defoliation height. To increase prairie grass production and persistence, rest intervals between grazings of 40 to 50 d are recommended, or alternatively, a management involving silage or hay cutting offers scope.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2494.1989.tb01933.x
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  • 2
    Electronic Resource
    Electronic Resource
    The Kinetics of the Reaction at Low Temperatures between Sodium Films and Thermally Activated Hydrogen (1966)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 70 (1966), S. 3681-3687 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100883a052
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  • 3
    Electronic Resource
    Electronic Resource
    The corrosion of copper in ethylene glycol-water mixtures containing chloride ions (1991)
    Springer
    Journal of applied electrochemistry 21 (1991), S. 358-364 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The anodic oxidation of copper at 25°C in 50% (w/w) ethylene glycol-water and in aqueous solutions has been studied by linear sweep voltammetry. The effect of chloride concentration at pH 0 and 3 has been explored. The results in both solvents follow a similar pattern. At pH 0 and in the absence of chloride, only one anodic peak is observed corresponding to the dissolution of copper metal as copper(II) ions. At intermediate chloride concentrations (0.01–0.03 M), two additional peaks are detected which have been attributed to the following reactions: $$\begin{gathered} Cu + Cl^ - \to CuCl + e^ - \hfill \\ CuCl \to Cu^{2 + } + Cl^ - + e^ - \hfill \\ \end{gathered} $$ When the chloride concentration is increased further, the three peaks gradually collapse back into one, corresponding to the dissolution of copper as a copper(I) chloro-complex. An additional peak appears at pH 3 which has been ascribed to the formation of copper(I) oxide. The results have been interpreted usingE-pCl diagrams determined for the copper-chloride system in both 50% ethylene glycol-water and aqueous solutions. Further information has been obtained from rotating disc measurements and from microscopy. The relevance of these results to corrosion in automotive cooling systems is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01020222
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  • 4
    Electronic Resource
    Electronic Resource
    A kinetic and electrochemical study of the zincate immersion process for aluminium (1995)
    Springer
    Journal of applied electrochemistry 25 (1995), S. 659-666 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract To plate aluminium, its surface is often first coated with a thin layer of zinc which is formed by immersion in an alkaline zincate solution. This paper describes a kinetic and electrochemical study of the zincate immersion reaction. Using an aluminium sample in the form of a rotating disc, the effects of varying the zinc concentration (0.01–0.5 m), disc rotation speed (66–1380 rpm), temperature (5–72°C), and sodium hydroxide concentration (1.5–9.0 m) on the kinetics were investigated. It was found that the reaction was usually first order. When the zincate concentration was 0.1 m, the reaction was chemically controlled with an activation energy of 35 ± 7 kJ mol−1. At high zincate concentrations, high disc rotation speeds and low sodium hydroxide concentrations, a thin film of zinc metal was formed on the aluminium surface, blocking the subsequent reaction. It was found that the most compact and adherent zinc films were formed at high zincate concentrations. This finding is consistent with industrial practice. These results are explained using mixed potential measurements and Evans' diagrams.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241927
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  • 5
    Electronic Resource
    Electronic Resource
    The chronopotentiometric method for measuring the kinetics of metal dissolution and cementation reactions (1996)
    Springer
    Journal of applied electrochemistry 26 (1996), S. 509-514 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The validity of the chronopotentiometric method, which has been used for studying the kinetics of metal dissolution and cementation (displacement) reactions was examined. Using the dissolution of electrodeposited zinc films as an example, results are presented for the dissolution in a triiodide solution, in an acid solution and in an acidified triiodide solution. The effect of the substrate electrode, on which the zinc film is deposited, was found to be negligible in the case of the triiodide dissolution reaction which is known to be diffusion controlled. However, the substrate electrode can have a profound effect on the dissolution in acid, a reaction which is known to be chemically controlled. In addition, the apparent dissolution rate in acidified triiodide solutions can be greater than the sum of the separate dissolution rates. Explanations for these findings, based on the catalytic effect of the substrate electrodes, are presented. The applicability of the chronopotentiometric method to the cementation of copper (II) on to electrodeposited zinc filsm was also investigated. Similar difficulties to those found with the zinc/acidified triiodide system were encountered. As a result of the understanding of the pit-falls of the chronopotentiometric method developed in this work, it was possible to review critically previous measurements of this type, which have been reported in the literature. It was concluded that, while the majority of previous studies are correct, a serious error has been made in one paper.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01021974
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation and characterization of surface modified electrodes from hydroxyanthraquinones (1988)
    Springer
    Journal of applied electrochemistry 18 (1988), S. 368-373 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The preparation of polyphenylene oxide polymer films has been extended to the anthraquinone series. Potentiostatic and cycled potential procedures have been utilized in the anodic polymerization of several hydroxy-substituted anthraquinones producing surface modified electrodes incorporating the quinone moiety. The electrochemical response of such electrodes was investigated in aqueous media and the stability of the films was evaluated under moderately harsh testing conditions, simulating the environment of a lead-acid battery electrolyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01093750
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  • 7
    Electronic Resource
    Electronic Resource
    A capacitance study of the silver(I)/copper displacement reaction (1997)
    Springer
    Journal of applied electrochemistry 27 (1997), S. 59-63 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Metal displacement (cementation) reactions are usually diffusion controlled and conform to first order kinetics. When a displacement reaction is carried out in a batch reactor, positive deviations from a first order rate plot are commonly observed once the deposit becomes sufficiently thick. It has been suggested that these rate enhancements are the result of changes in deposit structure resulting in increases in surface area. Another theory argues that the rate enhancements are due to turbulence associated with increasing roughness of the deposit. In this paper, an attempt is made to discriminate between these two possibilities by measuring the capacitance of a copper electrode immersed in a silver(I) solution. It was found that no anomalous capacitance changes were observed corresponding to the region in which rate increases were observed. This suggests that turbulence effects, rather than area effects, are responsible for the increased reaction rate. Capacitance measurements were also conducted for the reaction between silver(I) and copper in the presence of cyanide which caused the silver to deposit in a thin uniform layer on the copper surface, thus blocking the displacement reaction. It was found that the capacitance changed very little with time under these circumstances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026466916019
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  • 8
    Electronic Resource
    Electronic Resource
    The role of iron(iii) and tartrate in the zincate immersion process for plating aluminium (1997)
    Springer
    Journal of applied electrochemistry 27 (1997), S. 799-804 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The zincate immersion process is a commercial process used to treat aluminium prior to electroplating. Superior zinc coatings are obtained through modifications to the original process. One such modification involves the addition of ferric chloride, complexed with potassium sodium tartrate, to the plating baths. This paper describes a detailed investigation into the function of these additives. It was found that the addition of tartrate alone did not significantly affect the rate of zinc deposition, the deposit morphology or the position of the aluminium or zinc polarization curves. This suggests that the role of tartrate is solely as a complexing agent to maintain iron (iii) in solution. In contrast to this, the addition of iron(iii)/tartrate had a marked effect on the reaction. It was found that iron(iii) functioned primarily by reducing the size of the zinc crystals as they formed. This produces a thinner and more compact zinc immersion coating.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018468627773
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  • 9
    Electronic Resource
    Electronic Resource
    Long Term Effects of Midbrain Stimulation on 5-Hydroxyindole Synthesis in Rat Brain (1970)
    [s.l.] : Nature Publishing Group
    Nature 226 (1970), S. 84-85 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] 250 g male rats were anaesthetized with 1 per cent fluothane in oxygen and a concentric bipolar stainless steel electrode was inserted into the raphe nuclei at AP + 0.5; L 0.0; H 2.6. Stimulation with 36 V, 2 ms square wave pulses at 10 s1 was applied to the raphe for 1 h. Although an electrode was ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/226084a0
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  • 10
    Electronic Resource
    Electronic Resource
    Rate of Hydrogen Dissociation at a Hot Tungsten Surface (1970)
    [s.l.] : Nature Publishing Group
    Nature 227 (1970), S. 704-704 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Langmuir used two techniques to measure the atomization rate. The first relates the rate of heat loss from a tungsten filament in a hydrogen atmosphere to the atomization rate, and is the more reliable2. In the second, the rate of removal of hydrogen by an "atom trap" is assumed to be equal to the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/227704a0
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