In order to study the curling behavior of croched fabric quantitatively, yarn tension and thickness of crochet-hook are changed and those effects on loop length and curvature of the croched fabric are investigated. Following results were obtained. Curling behavior of croched fabric is in proportion to yarn tension at basic operation of knitting. This is because that the larger the yarn tension, the shorter the unit loop length, and the recovery elastic torque per unit length becomes larger. Curling behavior of croched fabric is inversely proportional to thickness of croched-hook. This is because that the bigger the thickness, the longer the unit loop length, and the recovery elastic torque per unit length becomes smaller. Theory concerning basic operation of croched fabric proposed in the former paper8 is proved to be valid.
(Received November 9, 1992)
(Accepted for Publication November 2, 1993)

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Color discriminate region of woven fabrics is studied through the perceived color difference of experts employed in color inspection. The correlation coefficient between perceived color difference (ΔE_p) by experts and colorimetric ones (ΔE^∗_ab) was very high.
Color discriminate region which experts had a long term experience on the color differences is established in a smaller one than MacAdam's just noticeable difference (jnd) given by light source.
And an approximate ellipse which correspond to MacAdam's ellipse plotted in a^∗ b^∗ diagram can make use of the judgement of color differences.

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This paper is related to the study on the influence of the top card clothing with highly sharpened tooth point on the carding efficiencies such as carding action, removing trash and so on.
The top card clothing with sharpened tooth point i.e.a new type of the top card clothing is compared with anold one.
The follwing results are obtained by the experiments mentioned above.
(1) The number of neps in the sliver made by the new type of top card clothing is much less than that by the old one.
(2) The number of trashes in the sliver made by the new type of top card clothing is much less than that by the old one, when the new type has not yet warn out.
(3) Trash content and lint content in the top waste with the new type of top card clothing remain approximately constant irrespective to test conditions.
(4) Coefficient of kinetic friction between the tooth point and the fibre becomes higher when the tooth point is more sharpened.
(5) Orientation of fibre on the top flat are improved when the tooth points is more sharpened.
From the above results, it is concluded that the sharpened tooth point of the top card clothing is improved for carding.

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