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  • 1
    Electronic Resource
    Electronic Resource
    Free vibrations of viscoelastic materials with high damping (1984)
    Springer
    Colloid & polymer science 262 (1984), S. 387-396 
    Details
    ISSN: 1435-1536
    Keywords: Viscoelasticity ; free vibrations ; dynamic modulus ; model calculations ; Fourier analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The theoretical basis for the determination of dynamic moduli of viscoelastic materials using free vibrations is critically reviewed. A new method is proposed which consists in a Fourier analysis of the response of the viscoelastic material to a pulse. This pulse spectrometry should offer a number of advantages, notably an unproved accuracy of the measurements, independence from critical damping conditions and determination of the dynamic moduli within a frequency window in one experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01410257
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Quantitative shape analysis: A review (1981)
    Springer
    Mathematical geology 13 (1981), S. 303-320 
    Details
    ISSN: 1573-8868
    Keywords: sedimentology ; outline shape ; Fourier analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract Sedimentologists, among others, have been accustomed to the analysis of the shape of sedimentary particles. Recently such shapes have been subjected to more quantitative analysis, almost completely removing the subjective element so long inherent in the various indices. However, these quantitative analyses themselves are not free from qualitative bias, partly displayed in the choice of appropriate technique, and to some extent in the intermediate steps of the data collection and analysis. Various numerical methods are introduced within the framework of a typology based on whether the analysis is performed on the grain considered as an outline, or as a planar surface. Nine desirable properties are suggested, as a yardstick against which to evaluate the descriptors. In all these techniques the object is to examine a discrete approximation of single items, in two dimensions only. Some of the methods are nevertheless applicable to three dimensions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01031516
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ophthalmodynamography and ophthalmodynamometry in neurological practice (1980)
    Springer
    Documenta ophthalmologica 49 (1980), S. 97-153 
    Details
    ISSN: 1573-2622
    Keywords: Ophthalmodynamography ; Ophthalmodynamometry ; Carotid obstruction ; Stroke ; Fourier analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Inventarisation of atraumatic methods of analysing the circulation in the carotid region shows that they generally can be classified as physiological or anatomical. Physiological methods focus on blood circulation time or on the pulsating changes in blood pressure, blood velocity, blood vessel diameter and cerebral volume. In this study the reliability of two pressure-dependent methods, namely ophthalmodynamography and ophthalmodynamometry, for the detection of haemodynamically significant carotid stenosis is established. Correct results were found in 78–82% of cases. Ophthalmodynamography, and the advantage of combining this method with ophthalmodynamometry, are more extensively investigated. Although in recent years attention has been focussed on the study of the blood velocity pulsations with the Doppler technique, maximal diagnostic efficacy can be expected from a combination of pressure and flow wave studies. A way to compare all the information contained in the curves can be found in the technique of Fourier analysis. The results obtained by Fourier analysis of the ophthalmodynamographic curves are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175177
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Frequency analysis of the surface electromyogram during sustained isometric contractions (1980)
    Springer
    European journal of applied physiology 43 (1980), S. 173-182 
    Details
    ISSN: 1439-6327
    Keywords: Exercise ; EMG ; Fourier analysis ; Fatigue ; Skeletal muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four male and four female volunteers served as subjects in these experiments to assess the frequency components of the surface EMG during and following brief (3 s) and sustained isometric contractions of the handgrip muscles. Two types of fatiguing contractions were performed. Contractions were either maintained to fatigue at a constant tension of up to 100% of their strength or were maintained as a sustained maximal effort in the unfatigued or previously fatigued muscle. The frequency components of the surface EMG were assessed by calculating the power spectra of 1.5 s samples of the EMG from a fundamental frequency of 4 Hz through the first 128 harmonics by Fourier analysis; the centre frequencies of the resultant power spectra were then used as an index of the mean frequency of the EMG. The results of these experiments showed that the centre frequency was independent of the tension exerted by the muscle during brief isometric contractions but decreased linearly with time throughout the duration of fatiguing isometric contractions at tensions between 25 and 100% MVC. During sustained maximal effort, the frequency initially decreased linearly with time. However, once the target tension could no longer be maintained, the centre frequency remained constant throughout the remainder of the contraction. The frequency was found to recover within 1 min following exercise at all tensions examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422448
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Fourier packing ordinate: A univariate size-independent measurement of the polygonal packing variation in Paleozoic bryozoans (1980)
    Springer
    Mathematical geology 12 (1980), S. 139-156 
    Details
    ISSN: 1573-8868
    Keywords: Fourier analysis ; harmonic analysis ; packing ; principal components ; spatial analysis ; bryozoans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The Fourier packing ordinate provides a highly sensitive, univariate, and size-independent measurement of the polygonal packing variation in Paleozoic bryozoan colonies. It is potentially useful in quantifying a wide variety of natural packing arrays or polygonal networks, and is preferable to counting the sides of polygons, the frequency of triple or quadruple junctions, the nearest-neighbor statistic, measurements of surface area per unit cell, or individual harmonic amplitudes. Fourier shape analysis provides exact measurements of the levels of two- to six-fold rotational symmetry in all natural packing gradients. In bryozoans these symmetries are intercorrelated because as each order of symmetry is increasing, the previous order is decreasing. Shapes in these packing arrays are normally hybrids of two or more orders of rotational symmetry. The levels of rotational symmetry involved in these packing gradients are significantly correlated with a single principal component, the Fourier packing ordinate, which is independent of both size and cell boundary phenomena. Spatial analysis of the Fourier packing ordinate within an Ordovician bryozoan colony reveals both variation in packing caused by subcolony budding, as well as large scale trends which vary from the colony center to the free-growing margin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01035245
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    Paper (German National Licenses)
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