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  • 1
    Electronic Resource
    Electronic Resource
    Separating temporally-overlapped waveforms with electrooptic sampling (1996)
    Springer
    Optical and quantum electronics 28 (1996), S. 953-960 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The authors report on a new approach in ultrafast characterization of electronic devices to recover temporally-overlapping incident and reflected signals near a device. The technique involves electrooptic measurement at two locations. With suitable processing, the measured waveforms can be decomposed into components propagating towards and away from the device. Experimental results for coplanar structures are shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00820160
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  • 2
    Electronic Resource
    Electronic Resource
    Rate effect on interfacial response between fibres and matrix (1995)
    Springer
    Materials and structures 28 (1995), S. 83-91 
    Details
    ISSN: 1359-5997
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Description / Table of Contents: Resume On a étudié l'effet d'arrachement, à différentes vitesses de glissement, de fibres scellées dans une matrice de ciment. On a établi un système de mesure pour le ‘pendule Charpy’, qui permet d'utiliser deux méthodes indépendantes pour évaluer l'arrachement des fibres du ciment. On a essayé deux séries d'éprouvettes de 16 et 8 fibres, et on a examiné l'effet de la vitesse de glissement et du nombre de fibres. On propose un modèle théorique basé sur la mécanique de la rupture, qui prédit l'effet de la vitesse de glissement sur l'arrachement des fibres. Le modèle proposé, qui s'appuie sur la force maximale d'arrachement des fibres d'un modéle de référence à faible vitesse, peut prédire les forces maximales d'arrachement ainsi que les déplacements correspondant à des vitesses de glissement supérieures.
    Notes: Abstract A study on steel fibres pulled out from a cementitious matrix at different slip rates was conducted. A measurement system, which allows one to use two independent methods to evaluate pull-out load, was developed for the Charpy pendulum. Two series of specimens, with 16 and 8 fibres, respectively, were tested. Effects of the rate of slip and of numbers of fibres on interfacial behaviour have been examined. A theoretical model to predict the slip-rate effect on fibre pull-out has been proposed based on fracture mechanics. Based on the peak fibre pull-out load of a reference specimen with a static slip-rate, the proposed model can predict peak pull-out loads and corresponding slips at faster slip-rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02473175
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  • 3
    Electronic Resource
    Electronic Resource
    Evolutionary Maximum Entropy Spectral Estimation and Heart Rate Variability Analysis (1998)
    Springer
    Multidimensional systems and signal processing 9 (1998), S. 453-458 
    Details
    ISSN: 1573-0824
    Keywords: non-stationary time series ; evolutionary spectral theory ; spectral analysis of heart rate variability ; cardiovascular time series
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Spectral analysis has been used extensively in heart rate variability (HRV) studies. The spectral content of HRV signals is useful in assessing the status of the autonomic nervous system. Although most of the HRV studies assume stationarity, the statistics of HRV signals change with time due to transients caused by physiological phenomena. Therefore, the use of time-frequency analysis to estimate the time-dependent spectrum of these non-stationary signals is of great importance. Recently, the spectrogram, the Wigner distribution, and the evolutionary periodogram have been used to analyze HRV signals. In this paper, we propose the application of the evolutionary maximum entropy (EME) spectral analysis to HRV signals. The EME spectral analysis is based on the maximum entropy method for stationary processes and the evolutionary spectral theory. It consists in finding an EME spectrum that matches the Fourier coefficients of the evolutionary spectrum. The spectral parameters are efficiently calculated by means of the Levinson algorithm. The EME spectral estimator provides very good time-frequency resolution, sidelobe reduction and parametric modeling of the evolutionary spectrum. With the help of real HRV signals we show the superior performance of the EME over the earlier methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008435130351
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of microbial concentration on the rheology of non-Newtonian fermentation broths (1999)
    Springer
    Applied microbiology and biotechnology 51 (1999), S. 310-315 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The objective of this study was to quantify the effect of fungal biomass concentration on the rheology of non-Newtonian fermentation systems. Batch fermentations of Penicillium chrysogenum were carried out with glucose as the sole carbon source. The flow behavior of the system was characterized at various fermentation times and was adequately described by the power-law model. The apparent viscosity of the fermentation broth was significantly affected by biomass concentrations in the fermenter. Fermentation broths containing 17.71 g/l biomass as dry weight were characterized by an apparent viscosity of 0.25 Pa s at a shear rate of 50 s−1. Microbial concentration also affected the power-law flow-behavior index and the consistency index. The value of the consistency index ranged from 0.002 Pa s n at a biomass concentration of 0.1 g/l to 6.14 Pa s n at a biomass concentration of 17.71 g/l. The flow-behavior index decreased from an initial value of 1 to a final value of 0.17. Simple empirical correlations have been proposed to quantify the dependence of the power-law parameters on fungal biomass concentration. Experimental data obtained in this study were accurately described by these correlations. The general applicability of these relationships was tested, using previously published rheological data on Aspergillus awamori and Aspergillus niger fermentation broths, and good agreement was seen between experimental data and the predictions from the empirical correlations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002530051396
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of the paste-aggregate interfacial transition zone surface roughness and its relationship to the fracture toughness of concrete (1995)
    Springer
    Journal of materials science 30 (1995), S. 3149-3154 
    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 Notched concrete beams containing varying amounts of pea gravel aggregate were tested under three-point bend, and their fracture toughness determined. The roughness of the region near the interface between the cement paste and the aggregate was evaluated by digitizing images from a confocal tandem scanning microscope. The average roughness of the paste was found to be related to the fracture parametersK IC (critical stress intensity factor) and Δa c (critical crack extension), as determined by the two-parameter fracture model. The roughness in the proximity of the paste-aggregate interface was generally higher than that of the paste far from the aggregate, and it decreased with the distance from the aggregate. This study indicates that aggregate particles increase the toughness of the cement paste portion of concrete, and that this is an important mechanism for toughening concrete.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01209230
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  • 6
    Electronic Resource
    Electronic Resource
    Enhanced nucleation and growth of diamond thin films using a nanodiamond monolayer (1997)
    Springer
    Journal of materials science 16 (1997), S. 476-478 
    Details
    ISSN: 1573-4811
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Abstracts are not published in this journal
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018568427678
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  • 7
    Electronic Resource
    Electronic Resource
    The effects of bromocriptine and prolactin on porphyrin biosynthesis and morphology in the female hamster Harderian gland (1996)
    Springer
    Journal of comparative physiology 166 (1996), S. 144-149 
    Details
    ISSN: 1432-136X
    Keywords: Porphyrin ; Harderian gland ; Bromocriptine ; Prolactin ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Porphyrin biosynthesis was examined in the Harderian gland of the female golden hamster by fluorometric assays of gland porphyrin content and by measuring the activity of a rate-limiting enzyme for haem biosynthesis, δ-aminolaevulinic acid synthase. Both porphyrin content and enzyme activity are high in normal female glands. Enzyme activity was lowered in females ovariectomised for 6 weeks, and both enzyme activity and porphyrin content were greatly lowered in ovariectomised females given the dopamine agonist bromocriptine; this suppression could be prevented by simultaneous prolactin administration. Bromocriptine (but not ovariectomy alone) also masculinised the morphology of the Harderian gland, resulting in the appearance of type II cells and polytubular complexes; again, the simultaneous administration of prolactin prevented masculinisation. The results support the hypothesis that while androgens have an inhibitory effect on porphyrin synthesis within this model, prolactin may have a major facilitatory role.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301178
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  • 8
    Electronic Resource
    Electronic Resource
    The effects of bromocriptine and prolactin on porphyrin biosynthesis in the Harderian gland of the male hamster, Mesocritecus auratus (1995)
    Springer
    Journal of comparative physiology 164 (1995), S. 524-529 
    Details
    ISSN: 1432-136X
    Keywords: Porphyrin ; Harderian gland ; Bromocriptine ; Prolactin ; Hamster, Mesocritecus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Porphyrin biosynthesis was examined in the Harderian gland of the male golden hamster by fluorometric assays of gland porphyrin content and by measuring the activity of a rate-limiting enzyme for haem biosynthesis, 5-aminolaevulinic acid synthase. Both porphyrin content and enzyme activity are low in normal male glands but were greatly raised in males castrated for 6 weeks. However, porphyrin synthesis remained at basal levels in castrates given the dopamine agonist bromocriptine; this suppression could be reversed by simultaneous prolactin administration, and castrated males receiving prolactin alone exhibited very high enzyme activity and porphyrin content. Bromocriptine also prevents the morphological feminisation of the Harderian gland which would normally occur after castration; again, the simultaneous administration of prolactin permits feminisation to occur. The results support the hypothesis that, while androgens have an inhibitory effect on porphyrin synthesis within this model, other factors, including prolactin, are permissive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261392
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  • 9
    Electronic Resource
    Electronic Resource
    Measurement of deformations on concrete subjected to compression using image correlation (1997)
    Springer
    Experimental mechanics 37 (1997), S. 307-313 
    Details
    ISSN: 1741-2765
    Keywords: Concrete ; feedback signal ; fracture ; digital image cross correlation ; nondestructive evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Because the nature of failure in concrete is complicated due to the material heterogeneity, a robust measuring method is essential to obtain reliable deformation data. A nondestructive displacement evaluation system using a digital image cross-correlation scheme, often called computer vision, is developed to make microscopic examinations of the fracture processes in concrete. This is a full-field measuring method that gives an accuracy within the micron range for a 100 mm × 75 mm viewing area. A feedback signal that combines the lateral and axial deformations provides a well-balanced imaging rate both before and after the peak load. Displacement vector diagrams or displacement contour maps of concrete reveal highly nonuniform deformations even in the elastic range. The processes of fracture in concrete are well defined at different deformation levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02317423
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  • 10
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    Influence of microbial concentration on the rheology of non-Newtonian fermentation broths (1999)
    Springer
    Details
    Publication Date: 1999-03-26
    Print ISSN: 0175-7598
    Electronic ISSN: 1432-0614
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Springer
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