Dynamic properties represented by curved load-elongation diagrams of textile fibers have been re-examined to obtain suitable values for their elastic properties. For this purpose, we have used the logarithmic strains ln(l/l₀) for longitudial and ln(r/r₀) for lateral, and Poisson's logarithmic ratio μ_l=-(dr/r)/(dl/l). The authors also defined Young's logarithmic modulus, E_l=(W/s)/{(l/l₀)-2μ_l ln(l/l)}, which are based on the logarithmic strains. The decrease in the cross-sectional area accompanying a longitudinal extension of a textile fiber has been studied together with its Poisson's ratio. The results:
1) A testing machine based on the principle of an air-micrometer makes it possible to record continuously both longitudial and lateral contractions.
2) Nylon-6 fishing lines show an almost constant Poisson's ratio of μ=0.385_??_0.386 until the longitudial strain reaches 11_??_13%. Beyond that point, the lateral strain changes its trend and Poisson's ratio reaches as much as μ=0.446 at the breaking point.
3) Fluctuations in the strain diagram are presumably due to the instability of a lateral -vs. -longitudial strain diagram.

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When an automatic weigh feeder is used on a worsted card, the discountinuous operation of the weigh feeder unavoidably causes periodic weight variations in the card sliver. While slivers from a number of cards are combined on the railwayballing head, the periodic weight variations in the individual card slivers are superimposed on the combined slivers and create periodic weight variations, with irregularly changing amplitudes. A slow weight variation due to a change in wool moisture also shows on the combined slivers.
The authors have designed an automatic sliver weight control device based on the open-loop control principle and used it on the railway-balling head to reduce weight variations in combined slivers. The control device has been found to eliminate periodic weight variations almost entirely, provided their wave length is more than 2 meters in terms of card slivers.

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In using metallic card clothing for cotton processing, the most important step to be taken is to reduce impurities-neps and other imperfection-in the sliver and, therefore, in the yarn. A number of comparative spinning tests has been made of two types of card: (a) MC, equipped with several tooth angle combinations of metallic card clothing on the cylinder and on the doffer; (b) FC, equipped with an ordinary wire fillet clothing.
The behavior of impurities has been minutely analyzed in each case. The impurities discharged into various parts of a card have been classified into four kinds by their structures and into six classes by their sizes. It has been concluded from the tests that neps are always fewer in a sliver on MC than in a sliver on FC, because there is a smaller deposit of fibers on MC's cylinder and flats and, therefore, there is less nep formation.
It has been concluded also that the other kinds of impurities in a sliver on MC can also be made fewer than in a sliver on FC if the tooth angle combination is properly adjusted. The proper adjustment is to make the tooth angle large on the cylinder and small on the doffer. This reduces the fiber density on the cylinder surface, improves the impurity-removing ability of the flats, and lessens the impurities in the sliver. These results have been confirmed again by the fact that yarns spun from an MC-processed slivers get a better rating for neps and other imperfections in an appearance test. Since there is no appreciable difference in the quality of the yarn except in the impurities, metallic clothing can be very profitably used for cotton spinning also.

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Injection of the weft by air-jet into the free air or shed has been studied with the aid of several experimental devices. The main results obtained from this study are:
1. A nozzle with a simple tapered cylinder for its base and having a parallel tip 50mm long and 10mm in diameter gives the best performance in propelling the weft more than 100cm when the thread guide is set 20mm inside the nozzle outlet.
2. Laval tubes are unfit for weft propulsion.
3. The air speed drops sharply near the nozzle, and is exceeded, in the middle of the shed, by the running speed of the weft.
4. How to remove the point whene the air speed is exceeded by the running speed of the weft as far as possible from the nozzle with the least possible additional comsumption of horsepower for air compression is a problem which awaits further inquiry.

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One of the most important things in eliminating electrification hazards is the removing of electric charge, especially when a textile material is subjected to rubbing more than once. In this article the electrification of textiles is represented by an equivalent closed circuit. Results of the author's experiments are as follows:
(1) Electrification of textiles can be represented by a D. C. circuit.
(2) The circuit theory suggests that the generation of static charge on textiles is affected by a series of resistances or by an external electromotive force, and this is proved by the author's experiments.
(3) These facts can be used as static eliminators.
(4) Static eliminators based on corona works on two types of neutralization.

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Object of study:
Fly, or cotton dust, is generated in each manufacturing process in spinning mills. It accumulates on the machines, on the floor and in other places, and lowers the quality of yarns. One method of removing fly is to blow it off and suck it away with air flow. This article deals with the theoretical aspect of the sucking of dust particles.
Results of study:
1. The following experimental formulas on the critical velocity V (m/s) of cotton tufts and sand grains have been obtained:
V=aln√G/s+b for cotton tufts
where:
where G=weight of a cotton tuft. (kg)
S=effective maximum area in which air flow works. (m²)
a=1.13, b=1.66 for rolling movement of linear cotton tufts
a=1.00, b=1.97 for rolling movement of spherical cotton tufts
a=1.84, b=2.26 for sliding movement of linear cotton tufts
a=1.51, b=2.65 for sliding movement of cylindrical cotton tufts
V=0.195 lnd+6.71 for sand
V=0.216 lnd+6.19 for molding sand
d: mean diameter of sand grains. (mm)
2. The following experimental formulas have been obtained for the terminal velocity Um (m/s) of cotton tufts and sand grains:
Um=8.35{G/S(1/γ-1/γ')}^0.38 for cotton tufts
Um=3.80 d^0.93 for sand
Um=6.49 d^1.28 for molding sand
where γ=specific weight of air. (kg/m³)
γ'=specific weight of a cotton tuft. (kg/m³)
3. We have analyzed air flow between the floor and the nozzle as a two-dimensional potential flow and theoretically obtained its transform equation and the velocity distribution on the floor.

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