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  • 1980-1984
  • 1970-1974  (3)
  • 1974  (3)
Material
Years
  • 1980-1984
  • 1970-1974  (3)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 26 (1974), S. 353-359 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Average radial growth rates of the hemispherical aragonite colonies deposited by the Indo-Pacific scleractinian reef coral Platygyra spp. were determined by measuring the thickness of density variations in the skeleton that are revealed by X-radiography. Ninety-one specimens from 21 localities were examined, but only 54 of these exhibited well-defined growth-banding. The apparent temperature dependence of growth rate is linear over the range 23.9° to 29.3°C, averaging 5.4±0.94 mm/year at 24°C, 8.0±0.42 mm/year at 27°C, and 9.7 ±0.58 mm/year at 29°C (90% confidence limits). Expression of the influence of temperature on growth rate in terms of the Arrhenius equation yields an activation energy of 20,680 cal/mole, which is comparable to values for typical biological reactions, but is only half that reported for skeletogenesis in another reef coral, Pocillopora damicornis, on the basis of controlled incubation studies involving 45Ca uptake.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 25 (1974), S. 734-739 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: The influence of imposed protection currents on the efficiency of inhibitors for cooling watersIn case where the cathodic protection of a cooling system is not feasible a combination of cathodic protection and inhibition may be of advantage. The authors have studied the potential influence of a direct current on the efficiency of an inhibitor; during the experimental work they have used a current intensity corresponding to the maximum intensity of the protection current used in practice. Using potentiokinetic methods they have found that the number of inhibitors which may be used in such conditions is rather small. In the case of inhibitors based on nitrites or amines the protecting efficiency is rather reduced after some hundred hours' operation under direct current, and in some case even a corrosion stimulation has been experienced. Inhibitors based on chromates and anticorrosion oil emulsions exhibit improved electrochemical stability, though, in the case of oils emulsion breaking must be taken into account after relatively short durations of operation.
    Notes: In Fällen, wo der kathodische Schutz eines Kühlsystems schwer durchführbar ist, erweist sich eine Kombination von kathodischem Schutz und Inhibierung als vorteilhaft. Die Verfasser untersuchten mögliche Einflüsse von Gleichstrom auf die Wirksamkeit von Inhibitoren; bei diesen Versuchen arbeiteten sie mit einer Stromstärke, welche der maximalen in der Praxis verwendeten Schutzstromstärke entsprach. Mit Hilfe von potentiokinetischen Methoden wurde gefunden, daß die zahl der unter diesen Bedingungen verwendbaren Inhibitoren sehr klein ist. Im Falle von Inhibitoren auf Basis von Nitriten oder Aminen verringert sich schon nach einigen Stunden Gleichstromeinwirkung die Schutzwirkung und in manchen Fällen zeigt sich sogar eine stimulierende Wirkung. Die Inhibitoren auf Basis von Chromaten oder Korrosionsschutzölemulsionen sind hingegen elektrochemisch gut beständig im Falle der Öle ist jedoch damit zu rechnen, daß die Emulsion schon nach verhältnismäßig kurzer Betriebsdauer bricht.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 316 (1974), S. 13-18 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Addition von Oxalessigester an 2,4; 3,5-Di-O-benzyliden-al-D-xylose 1 führt zum 3-Äthoxycarbonyl-3-desoxy-5,7; 6,8-di-O-benzyliden-D-gulo-oktulosonsäure-äthylester 2, aus dem man durch Erwärmen mit verd. Salzsäure in Dioxan die 2-Desoxy-D-gulo-heptose 3 erhält. Beim Schütteln mit konz. Salzsäure und Benzylmercaptan entsteht aus 3 unter Abspaltung von Wasser das [2-Hydroxymethyl-furanyl(5)]-acetaldehyd-dibenzylmercaptal 6. Der Ketosäureester 2 kann in einer Keto-(2 a) und in einer Enol-Form 2 b auftreten. Von letzterer leiten sich das 2,4-Di-O-acetat 4 und der 2,4-Di-O-methyläther 5 ab. Die D-gulo-Konfiguration der Verbindungen 2, 3, 4 und 5 wird durch Überführen des Methyläthers 5 in den O-Methyl-L-äpfelsäure-bis-(p-bromphenacylester) 10 bewiesen.
    Type of Medium: Electronic Resource
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