• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.166-173
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• 2014

A noncontact nondestructive testing (NDT) method is proposed to detect the damage of pipeline structures and to identify the location of the damage. To achieve this goal, a scanning laser source actuation technique is utilized to generate a guided wave and scans a specific area to find damage location more precisely. The ND: YAG pulsed laser is used to generate Lamb wave and a piezoelectric sensor is installed to measure the structural responses. The measured responses are analyzed using three dimensional Fourier transformation (3DFT). The damage-sensitive features are extracted by wavenumber filtering based on the 3D FT. Then, flaw imaging techniques of a pipeline structures is conducted using the damage-sensitive features. Finally, the pipes with notches are investigated to verify the effectiveness and the robustness of the proposed NDT approach.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.387-394
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• 1995

A simple method for determining the absorption coefficient of oxyhemoglobin and deoxyhemoglobin in human blood is proposed as an application of the complex propagation constant of a guided wave in a thin-film optical waveguide. A serial multichannel sample chamber is constructed on the waveguide to vary the interaction length between the evanescent field and the sample, and the dependence of the sensor response on the interaction length is investigated for the various concentration of two hemoglobins. The sensor response is linearly proportional to the interaction length and the concentration of two hemoglobins. The attenuation constant due to the evanescent field absorption between the samples is experimentally obtained with the designed sensor, and then the absorption coefficient is determined by the proposed method. The absorption coefficients determined by the proposed method fairly well coincided with those obtained by the conventional transmission measurement.