Optical couplers in which fibers are directly bonded to each other show potential for stable optical performance, therefor numerous proposals have been made in this area, particularly regarding glass fiber.
In this report, an attempt was made to bond plastic optical fibers and typical optical characteristics were compared with various other techniques. A prototype optical coupler employing plastic optical fiber with a diameter of 1mm was fabricated. For the techniques such as “bonding using an optical adhesive” and “thermal fusion via partial heating” which require stripping of the clad layer or other forms of pretreatment, conflicting relationships were found between the joined length, the distribution ratio and the excess loss. But with ultrasonic bonding employing instantaneous fusion for one second or less, stable results were obtained in the range where the excess loss is approximately 1 dB or less and the output ratio approximately 1:1.4. In particular, the permanent bonding technique employing ultrasonic energy minimizes the difference in refractive index at the bond surface, and thus is optically satisfactory.

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Effective tone of colour was quantitatively analyzed from psychological view points. The lightdark, deep-pale, and heavy-light feelings are the most fundamental factor. The feeling of colour was examined using various colours with the above factors in terms of correlate colourimetric values which are supposed to correlate with the effective tone. In visual experiments, each tested parson chose a worked from a pair of words, which expressed appropriately the impression on the specimens selected systematically from a colour space. The results indicated that the feeling is mainly affected by lightness and colour depth. The visual assessment was compared with lightness, colour depth and other colour parameters computed from the calourimetric values and a set of empirical formulae, which represented the feelings, were derived.

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The degradation of azo dyes such as Orange I_??_IV was investigated in an electrolyte solution containing chloride or bromide ions as halide ions with electrolysis. In the presence of halide ions, the electrolyzed degradation was accomplished because of the generated electrophilic halonium ions as active species with electrolysis that involve initial attack at azo groups. It was presumed that these degradations were due to the molecular structure of dyes relating to the existence of azo-hydrazone equilibria in hydroxyazo dyes and electron-donating group in aminoazo dyes. In the case of an electrolyte solution containing chloride ion, the degradation of dyes was significantly influenced by the pH of this electrolyte and decrease with rising pH. The ability of degradation with electrolysis was larger in bromide ion than that in chloride ion and the pH of electrolyte had no influence on the degradation in the case of bromide ion, compared with chloride ion.

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In order to measure the apparent Poisson's ratio of textile fabrics by uniaxial tensile testing, error mechanism was studied and new evaluation method was proposed. Using Lloyd-Hearle method, experimental mechanism and resulting error were investigated by comparison with theoretical FEM calculation with experimental data. In Lloyd-Heare method, theoretical error of apparent Poisson's ratio can be reduced by uniaxial tension testing at two extreme conditions, i. e. either at large (gauge length)/(sample width) ratio or at small ratio. When the gauge length is short, the experimental results were markedly affected by the slip between the chucks and sample. In order to correct the experimental error caused by the above reason, samples having various dimensions were utilized for the experiment. Some concrete examples to get apparent Poisson's ratios of fabrics by uniaxial tension test were also shown. This method is applicable for simulations of cloth draping and deformation which need apparent Poisson's ratios.

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Rate of weight loss of cellulosic fiber substrate by cellulase treatment was studied. The weight loss curves of cellulosic substrates by the cellulase treatment could be classified into two types. Fabrics of staple fibers such as cotton and linen broadcloths showed a weight loss curve that had at least two stages in weight loss process, whereas fabrics of filaments such as rayon taffetacloth showed a simple smooth decay curve. The two stages in the weight loss process of the fabrics of staple fibers could be attributed to the enzymatic hydrolysis and the mechanical removal of fuzz from the surface of the fabrics during the cellulase treatment. The weight loss curves of all cellulosic fabrics studied could be fitted to a linear combination of first order decay equation by a non-linear regression with high accuracy. Effects of cellulase concentration, mechanical action of treating apparatus and nature of surface of the fabrics on the rate of weight loss could be apparently represented by the simple decay equation.

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In the manufacturing process of glass fibers, the glass-fiber cake, in which the glass fibers are wound on a paper tube to form a cylindrical shape, sometimes collapses inwardly during the drying process in the hot air. In order to clarify the mechanism of this collapse, the water content, and the distributions of temperature and vapor pressure in a fiber layer of a model glass-fiber cake were measured in the drying process. As a result, the external pressure, which was caused by the steam pressure in the fiber layer, acting on the inner layer of the cake was attributed to the inward collapse of the cake.

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