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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 58 (1988), S. 152-157 
    ISSN: 1439-6327
    Keywords: Static exercise ; Dynamic exercise ; Heart rate ; Blood pressure ; Systolic time intervals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cardiovascular response to static exercise has often been quantified on the basis of a comparison between static handgrip and dynamic cycling exercise. It is then difficult to make precise comparisons because the physical units of work are not compatible. If the data from dynamic exercise can be used to predict the cardiovascular response to zero movement (static exercise) this would suggest that static exercise is not fundamentally different from dynamic exercise. Using leg extension exercise which lasted for 1 min, a set of weights was lifted repeatedly 50 times/min, through three different distances. On each occasion, the heart rate, systolic time intervals (STI) and systemic arterial blood pressure were monitored non-invasively. Regression analysis of heart rate (HR) or blood pressure (BP) against the distance moved by the weights was used to predict the heart rate or blood pressure that would be expected for static exercise. In addition the same responses were measured following 1 min of static exercise during which the weights were held up but not moved. Five subjects, trained in leg extension exercise, completed the four exercise sessions in a random order. A constant force was produced in each variant of the protocol and in the static exercise it amounted to 50% maximal voluntary contraction (MVC). The forces developed and the distance the weights were lifted were monitored. During this sustained static exercise at relatively low intensity the cardiovascular changes could be predicted from the responses induced by dynamic exercise. It is suggested that other factors are important in determining the cardiovascular response to exercise, not simply the mode.
    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 39 (1988), S. 401-405 
    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: Korrosion von Metallen in oxidierend-chlorierend wirkenden Medien bei hoher TemperaturDas Verhalten von Metallen, welche die Basis von Hochtemperaturlegierungen bilden, wurde in einem Gasgemisch mit 5,5% Sauerstoff, 0,96% Chlorwasserstoff, 0,86% Schwefeldioxid, Rest Argon, bei 900°C untersucht. Damit sollten die Reaktionsprodukte charakterisiert werden, speziell die flüchtigen Verbindungen, welche die handelsüblichen Legierungen in einer solchen Umgebung besonders schädigen. Aufgrund von thermodynamischen Überlegungen können die Potentiale der reaktionsfähigen Verbindungen in dem Gasgemisch bestimmt werden, wobei die Korrelation mit den potentiellen Reaktionsprodukten möglich ist. In diesem Gasgemisch sind die Oxide von Nickel, Kobalt, Chrom, Molybdän und Wolfram die stabilen Phasen für die entsprechenden Metalle, d.h. daß bei der Einwirkung des Gasgemischs die entsprechenden Oxidzunderschichten entstehen. Indessen werden die Reaktionen durch die Bildung flüchtiger Korrosionsprodukte kompliziert; das gilt speziell für Nickel, Kobalt und Molybdän. Auf Chrom entsteht zwar ein Cr2O3-Zunder, doch gibt es Beweise dafür, daß chlorhaltige Verbindungen bis zur Zunder/Metall-Grenzschicht vordringen können. Der Oxidzunder auf Wolfram ist nicht sehr schützend und wächst rasch, während der Zunder auf Molybdän flüchtig ist, so daß das Grundmetall rasch verbraucht wird.
    Notes: An investigation has been undertaken into the behaviour of metals which form the basis of high-temperature alloys in an argon -5.5% oxygen -0.96% hydrogen chloride -0.86% sulphur dioxide gas mixture at 900°C. The intention has been to ascertain the reaction products, with particular emphasis on the formation of volatile species which can cause considerable degradation of commercial alloys in this environment. From consideration of the thermodynamics of the gas system, the potentials of the reactive species can be determined and correlated with the possible reaction products. In this gas mixture, the oxides of nickel, iron, cobalt, chromium, molybdenum and tungsten are the stable phases with respect to the corresponding metals. Indeed, on exposure of the metals to the environment, the appropriate oxide scales are developed. However, the reactions are complicated by formation of volatile corrosion products, particularly for nickel, cobalt and molybdenum. Although a Cr2O3 scale is established on chromium, there is evidence for penetration of chlorine-containing species to the scale/alloy interface. The oxide scale on tungsten is not very protective and thickens rapidly while that on molybdenum is volatile, resulting in rapid consumption of the specimen.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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