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  • Electronic Resource  (5)
  • ultrasonics  (3)
  • Biochemistry and Biotechnology  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 177-196 
    ISSN: 1573-4862
    Keywords: Interfaces ; ultrasonics ; partial contact ; quasi-static
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A quasi-static model for the ultrasonic transmission and reflection at imperfect interfaces is developed. The interface is represented by a distributed spring, determined by the change in static compliance of the medium with respect to one with a perfect interface, and a distributed mass, representing excess mass at the interface. Comparison of the model predictions to exact solutions for two simple cases illustrates its accuracy at low frequencies. The spring stiffnesses can be derived from existing solutions for the elastic displacement of materials containing cracks and inclusions under static load. Results for a variety of cases are reviewed. Applications of the model to study the characteristics of partially contacting surfaces in several problem areas of current interest are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-4862
    Keywords: Beam propagation ; bimetallic weld ; Gauss-Hermite beam model ; finite element method ; ultrasonics ; anisotropic medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract In this paper, predictions of two models for the propagation of ultrasonic beams through a two-dimensional, bimetallic weld geometry are compared. The finite element method can predict beam propagation through quite general geometry with high accuracy. This model, however, requires significant computational time. On the other hand, the approximate Gauss-Hermite model offers considerably greater computational speed, but has lower accuracy in certain regions and cannot treat the most general geometries and inhomogeneities in material properties. This paper compares the performances of the two models for the case of the two-dimensional, bimetallic weld consisting of multiple layers, some of which have anisotropic properties. It is found that the results of the two models are in good agreement in the vicinity of the central ray, and that the deviation increases as one moves away from the axis. Also, as the beam propagates through multiple interfaces, the accuracy of the Gauss-Hermite solution decreases.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 107-123 
    ISSN: 1573-4862
    Keywords: ultrasonics ; transducers ; focusing ; refractior ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A scalar theory of the propagation of Gaussian ultrasonic beams through lenses and interfaces is presented. For radiation into a fluid, the Fresnel approximation is employed to derive the laws of propagation of Guassian beams (previously employed in the analysis of coherent optical systems). These are then generalized to situations commonly found in nondestructive evaluation by treating the effects of propagation through lenses and through curved interfaces at oblique incidence. A numerical example illustrates the ease with which insight into diffraction phenomena for complex geometries can be gained by this approach. The limitations imposed on the theory by aberrations and the scalar assumption are discussed, and the relationship of the Gaussian theory to the radiation of piston transducers is explored.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 5 (1984), S. 35-42 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Proteins visualised by Coomassie Blue staining of two-dimensional polyacrylamide gels of complex mixtures of brain proteins were blotted onto nitrocellulose sheets. The Coomassie Blue stain was transferred simultaneously and bound strongly to the nitrocellulose, giving a copy of the original gel pattern. Using specific antisera and a second antibody coupled to horseradish peroxidase, proteins in the original mixture could be detected on the nitrocellulose in quantities less than 25 ng. The Coomassie Blue and horseradish peroxidase stains were distinguishable by a suitable filter, allowing precise correlation of spots stained by Coomassie Blue with spots stained with the brown immunoperoxidase reaction product. The technique was used to identify related proteins in electrophoretograms of brain extracts from different animals.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: High resolution two-dimensional polyacrylamide gel electrophoresis has been used to detect a soluble protein in extracts of human kidney which was not present in the electrophoretograms of other human tissues. This protein, coded kidney-acidic protein-60 (KAP-60) was purified to homogeneity and was characterized as having a native molecular weight of 85000, a monomer molecular weight of 35 000 and an isoelectric point of 5.6. KAP-60 was devoid of detectable carbohydrate or phosphate groups. Injection of the protein into rabbits produced antisera which were used to develop a radioimmunoassay for the protein and to localize the protein to specific cells within the kidney by the immunoperoxidase technique. A survey of human tissues by radioimmunoassay showed that KAP-60 was present in human kidney at approximately 150 times the concentration found in human liver and 300 times the level found in other human organs examined. Immunohistochemistry localized the protein to the proximal and collecting tubules in the kidney with no staining of glomeruli or distal tubules. The present study illustrates the use of high-resolution two-dimensional electrophoretic techniques in the detection of human tissue-specific proteins which may prove of clinical value in the biochemical diagnosis of tissue-specific damage.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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