Atsuo Shibuya

Crackles in asbestos workers: Auscultation and lung sound analysis

We surveyed 270 asbestos factory workers and 222 control subjects matched for age to assess the usefulness of listening for fine discontinuous adventitious lung sound (fine crackles) in detection of the early stages of interstitial fibrosis of asbestosis. Fine crackles at both bases were heard more frequently in asbestos workers (32.2%) than in controls (4.5%) (P less than 0.01). The presence of bilateral basal crackles was related to the duration of asbestos exposure and occurred before abnormalities could be detected by chest radiography. Two observers examined 74 workers randomly chosen from among 270 asbestos workers and found inter-observer agreement to be high (91.9%). There was close agreement between findings on chest auscultation and sound recordings.

Acoustic Microscopy Evaluation of Polypropylene/Calcium carbonate Composites

Dispersion behavior has been characterized by acoustic microscopy method for polypropylene (PP) filled with calcium carbonate (CaCO3). The heterogeneous structure of the large size such as aggregate, agglomerate of the filled particles and presumably void at polymer-particle interface possessing modulus heterogeneity in the compounds were evaluated. Binarization method was carried out in order to obtain area fraction of the structure. The relationship between dispersion behavior and content, size and surface treatment of the filler, and the mechanical property (elongation at break) has been investigated. The heterogeneous structure was inclined to increase with the increase in CaCO3 content and the decrease in CaCO3 particle size. The heterogeneous structure in composites filled with CaCO3 of various particle sizes markedly decreased by the surface treatment of CaCO3. While, the elongation at break of PP/CaCO3 composites could roughly be expressed as a function of aggregation or agglomeration fraction calculated from ultra-sonic image.

Measuring the Distribution of Local Deformation on Fabrics in the Tensile Process

A technique using a CCD camera system is proposed for measuring simultaneously the local displacements at many points on a deformed fabric in the tensile process without contacting with the sample. The local displacements can be transformed into local plane strains and a characteristic angle representing the global deformation. The distribution of strains on the fabric surface is characterized by the average and width of distribution of the local strains. The technique was applied to a few kinds of polyester fabrics and verified to be an effective means for clarifying quantitatively the distribution of local strains on fabrics extensively deformed.

Measurement for Mechanical Property of Sheets by Acoustic Transmission

A way of measurement of sheets such as fabrics or films for quality control in manufacturing processes was investigated. This way of measurement should be nondestructive, because of the constraint that the measurement has to be done within the process. Fundamental knowledge of this way of measurement by acoustic transmission was acquired to establish an method of measurement in the processing line.It was investigated by experiments on what the velocity of sound in sheets depends and does not depend.(1) In case of fabrics, the velocity of sound depends on the structure and the state of tension, and not on the length of fiber.(2) In case of films, the velocity of sound depends on the crystallinity, and not on the quantity of filler nor the thickness of films.

TRIAL ON AUTOMATIC MEASUREMENT OF THE DENSITY

There are many kinds of methods to measure the density, i.e. the number of warp and weft existing in the unit length of fabric. One of the methods to measure the density is to count the number of warp and weft yarns by ravelling the sample or by inspecting with textile analysis glass. Another method is a recognition of the pattern of cloths. The measurement by densi meter is an example of such pattern methods.While all these methods need the judgement by person, we developed a device to measure the density automatically by nondestructive inspection. Two methods, Fourier method and grille method, are proposed to analyze the optical images obtained by the device. The percentage of correct measurement varies according to the weave of the samples. More than 80% of the plain weave samples are measured correctly. Performance of the grille method is almost equal to that of the Fourier method.