The necking and molecular orientation of nylon-6 filaments in an industrial cold drawing process were studied by birefringence (Δn) of drawn filaments. The relation between the properties of drawn filaments and the drawing conditions were also considered, and the following results are obtained:
(1) When the filament is drawn with draw ratio of 4.0, its birefriengence (Δn) becomes the maximum immediately after the necking point.
(2) Δn reaches the e4uilibrium at the point where the filament speed is equal to the drawing speed.
(3) Δn becomes smaller between the drawing rolers and the winding bobbin.
(4) When the drawn filament is kept wound under tension, Δn increases with the lapse of time and reaches a constant value.
(5) Local Δn increases asymptotically with the distance from the feed roll when the yarn is drawn under the draw ratio 3.0, but Δn is approximately constant under the draw ratios of 3.5, 3.6 and 4.0. Δn of filaments drawn at high temperature is greater than that of yarns drawn at low temperature.
(6) The effect of the draw conditions, e.g., the draw ratio, the humidity in a drawing chamber etc., on Δn is also observed.
(7) Physical properties of filaments obtained under different drawing condition show that the molecular orientation is closely related to the filament properties.
(8) The drawing tension, molecular orientation and crystalization with various draw ratios are observed and their effects are also analysed.
(9) The winding tension on a draw-twisting bobbin was estimated from Δn of the wound filament.

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In the previous paper, a theoretical method for calculating the biaxial tensile property of two bar tricot fabrics had been presented.
In this paper, the accuracy of this theory has keen investigated by measuring the tensile properties of some actual fabrics by means of a biaxial tensile tester, and comparing the measured values with the theoretical ones.
The result shows that the fabrics knitted of fine or low-bulky yarns provide a very good agreement between the theoretical and experimental results. For the fabrics knitted of thick or high-bulky yarns, however, there is some discrepancy between them in some biaxial-deformation modes.
Two improvements have been done to this theory based on those observations: (1) the structure of the unit model has been corrected to be closer to the actual fabric structure, and (2) the compressive deformations of yarns in the needle and the sinker loops are calculated separately.
These improvements have made to the theory more useful for the practical design of almost all kinds of two bar tricot fabrics.

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In the previous paper, dynamic characteristics of a dancer roller as a detector of the feed control system of running materials were analysed, ignoring the presence of guide rollers. In the present study, are investigated the effects of the guide rollers on the detecting properties of the dancer roller.
The followings are the conclusions: 1) The dynamic characteristics of a dancer roller system with guide rollers are expressed by a set of simultaneous differential equations, and therefore the numerical calculation of the frequency response of the system requires to use an electronic computer. 2) The dancer roller performs as a detector of feed control under a certain limit of frequency. This limiting frequency is proved to be the minimum slackening frequency of the (n+1)-th member of the running material. 3) The frequency response of a virtual dancer roller, the equivalent rotating mass of which is a sum of all rollers in the actual dancer roller system, is a fairly good approximation of that of the actual system, in a range below the minimum resonance frequency. Thus the minimum slackening frequency of the virtual system coincides with that of the (n+1)-th member of the running material in the actual system.

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