An elastic influence of a viscoelastic liquid on the three-dimensional axisymmetric slow flow into a capillary has numerically been investigated for the Maxwell model by the perturbation method.Comparing the behaviour of the three-dimensional axisymmetric flow with that of the two-dimensional plane one, it was confirmed that there was a great difference betweenthem in the values of Weissenberg number at which a viscoelastic effect on flow began to appear. In addition, differences in shear and normal stress of three-dimensional axisymmetric flow were determined to compare them with those of two-dimensional ones. (Received October 6, 1977)

View full abstract

A model system of color analyzer is described which is completely different from conventional one provided with R, G and B filters.
The model system consists mainly of high-speed multi-spectrum color-separation-optics using Acousto-Optic Tunable Filter and a high-speed recognition mechanism of spectrun-pattern.
Good results on color recognition were obtained by using this method. It seems useful to have preliminary learning process of spectral distribution of picture element as characteristic-pattern data in the recognition mechamism, particulary when there are tone gradations in the drawings.

View full abstract

Yarn severances chiefly caused by yarn breakage in fabrics by a sewing needle have been an important problem in the sewing industry. The seriousness of this problem is indicated by the fact that many technicians ask to be informed on measures to be taken.
By sewing cotton knitted fabrics under various sewing conditions, the relation was obtained between various sewing conditions and the number of yarn severances.An investigation disclosed the factors which prevent cotton knitted fabrics from yarn severance; needle diameter, neele shape, diameter of hole on a throat plate, pressure of presser foot, lubrication of silicone to a sewing thread, sewing speed, fabric density, water content in a fabric, kind of fabric finishing (bleaching and softening). Yarn severance may considerably be reduced by combining these sewing conditions properly.
A study has also been made to develop a technique to measure the needle penetration force during highspeed sewing. By using this technique, the relationship was discussed between factors affecting on yarn severance and needle penetration force. The high correlation was found between maximum needle penetration force and an amount of energy required to drive a needle into a fabric in each sewing cycle. Penetration force of the stitch at which yarn severances are occurred is generally larger than that of the stitch without yarn severance.

View full abstract