Some of the tensile mechanical properties of viscose rayon and Nylon fibers, such as tensile stress behavior under repeated constant elongation, and stress-strain behavior after repeated constant elongation, are experimentally investigated. Also a comparison is made of these behaviors under repeated constant elongation and similar behaviors in a stress relaxation test or under static constant elongation.

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The relationship between Reynolds' number and the coeffecient of air resistance has been studied on mono-filament fibers by measuring the terminal velocity of fibers dropping spontaneously in stationary air. The results obtained are:
(1) With Reynolds' number R_e of a fiber defined as R_e=u_sd/v by using diameter d of the fiber to represent its size, it is possible to determine experimentally the relationship between the coefficient of air resistance C and Reynolds' number R_e as follows:
For mono-filament fibers C=24/(2.75R_e^0.756)
For cotton tufts C=24/(193R_e^2.00)
(2) The coefficient of air resistance for a mono-filament fiber is much smaller than Stokes' coefficient for a sphere or Lambs' coefficient for a cylinder, assuming the three to be equal in Reynolds' number.
(3) The effect of fiber crimp upon the coefficient of air resistance is so slight, in fact almost negligible.

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It is commonly accepted that a spinning frame shaking and eccentricity of bottom roll are the major causes of yarn unevenness. Nevertheless, spinning frames in many mills are not entirely free from such faults even today. Improvements in yarn quality are, therefore, possible by a strict supervision on draft rolls.
This article sums up the author's view on this problem based on his experiences in the plants of the Toyo Spinning Co., Ltd.
Causes for unsmooth revolutions of a bottom roll lie in:
(1) The roll itself
(2) Roll alignment
(3) Gear train that drive the roll
(4) Bearings supporting the roll
(5) Mishandling in the maintenance work

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The rate of the transfer of fibers from a cylinder to a doffer and the quantity of fibers on a cylinder have been investigated with the use of rayon staples carded with a flat card. The purpose is to get a proper distribution of fibers on the cylinder and thus increase production on a metallic card.
Results:
(1) P is constant irrespective of the fiber density on a cylinder.
(2) P is 6_??_7% on ordinary carding cloth and 9% on metallic carding cloth.
(3) To reduce P, it is helpful to reduce the working angle of the doffer metallic wire.
(4) The quantity of fibers on a cylinder is about 90 grains with ordinary carding cloth, about 68 grains with metallic carding cloth in the normal running state in which slivers of 280 grains/6 yards are carded. Both values are less than the quantity of sinking fibers between the carding cloth of a cylinder and the flat.
Therefore, by increasing P on a metallic card, it is possible to reduce the quantity of fibers on a cylinder and improve the efficiency of carding action.

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To analyze the fundamental behavior of a wool assembly in steeping and washing bowls, the author has studied the process in which an assembly floating on a liquid surface begins to sink. The time (t_{_??_}) needed for an assembly to begin sinking has been measured for various values of porosity (P_h) by using distilled water of various temperatures, trichlene and methyl alcohol of a normal temperature and a solution of non-ionic wetting agent of various concentrations (C_p) and of a normal temperature.
The difference in t_{_??_} between various values of P_h is small if the concentration of the wetting agent is high (dense). The difference in t_{_??_}, however, is high for a low concentration of the wetting agent, the maximum of t_{_??_} occuring at P_h=80%. The relation between log t_{_??_} and log C_p is practically linear and had a constant tangent if the porosity degree is fixed at a standard vlaue. When this wetting agent solution is used, the porosity arranged in order from fastest to slowest sinking of scoured wool is P_h=97>95>90>70>75>85>80%.

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Object of Study
To investigate the morphological state of a single filament in a twisted yarn and study the mechanism of twisting and the properties of the twisted yarn.
Results
(1) Twisting-induced migration has been investigated by dyeing a central filament and an outer-layer filament of a multi-filament nylon yarn.
(2) The migration of fiber is influenced by the tension of twisting. The smaller the tension, the wider the migration.
(3) Twisting induced by the twist counter is quite different in yarn structure from twisting produced by the twisting machine. The order of migration is higher in machine-produced migration.
(4) The structure of double twist has been clarified.

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A computation of frequency characteristics was made with the feeding device of typical weaving machines now used. It shows that:
(1) The automatic control device does not act efficiently if the unevenness of warp-tension exceeds 4_??_150 cycles per minute.
(2) When the tension unevenness is 5 to 7 cycles per minute, it is kept under control at 1/10.
(3) When the unevenness is 0.1 cycles per minute, it is kept under control at 1/10⁴.
(4) When the frequency is less than 80 cycles per minute, the weight-load-type shows better control characteristics than the spring-load-type.
(5) The weight-load-type has such an unique characteristic that the unevenness from 1 to 200 cycles per minute is kept under control at 1/1.8, irrespective of frequency.

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The 4 th international trade fair was held at Harumi pier near the center of Tokyo from 17 th April to 7 th May of this year.
Twenty eight countries participated in the fair and not only the scale of the fair was big but the number of visitors increased from 2.5 million to 1.9 million in comparison with the last year.
Most of the textile machines were exhibited in hall No. 10. In comparison with the last year's Osaka international trade fair, the number of exhibitors and exhibits were less in number, but there was progress in the content of the exhibits.
Here we are giving a report on it.

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