An attempt has been carried out to make tangling and opening parts in a yarn without a conventional interlaces, by running a truck which carries the yarn fastened at its both ends and then by exposing the yarn to an air jet in an instant. The action of the air jet on the yarn has been discussed. Moreover, the effect of the air pressure, the nozzle height which means the distance between the air jet nozzle and the upper surface of the truck fastening the yarn, the truck speed at which the yarn traverses the air jet, and the guide distance at which the yarn is fastened has been analyzed. Results obtained are as follows.
(1) The yarn subjected to the air jet in the experiment is similar to interlaced yarn produced by means of a conventional interlacer. Hence, interlaces is not essential to produce both tangling and opening parts in a yarn. Interlacer only plays a role to control cyclic production of both tangling and opening parts, and only the action of the air jet produces both of them.
(2) The opening part is produced at the position where the air jet blows, and the tangling parts exist at its both sides.
(3) The interlaced yarn is not always produced by the present method. Hence, repeating a lot of experiments and introducing the probability of production of interlaced yarn make later analyses easy. As a result, in the experiment the probability increases with increasing the air pressure and is maximum at 4.5kg/cm², over which it rapidly decreases. This tendency agrees well with the relationship between the air pressure and the number of tangles of interlaced yarn shown in a previous paper. The interlaced yarn can not be produced under the condition that the air pressure is controlled below 1.5kg/cm² or over 7.5kg/cm². The air pressure has little effect on the shape of both tangling and opening parts.
(4) Since the increase of the nozzle height corresponds to the decrease of the air jet force, the probability and the diameter of opening part reduce and the diameter of tangling part increases. However, since the region exposed to the air jet extends, the length of opening part radically increases.
(5) In the limit of the experiment, the truck speed at which the yarn traverses the air jet has very little effect.
(6) The probability increases with the increment of the guide distance, and shows a constant value of about 65% at the guide distance over 45mm. The interlaced yarn is not produced at the guide distance below 20mm. The standard deviation of the length of opening part becomes larger in proportion to the guide distance.

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Drag problems of fluid flow passing through fiber assembly which was made of short copper coils were studied experimentally. For the flow in which Darcy's law is valid, linear relationship between pressure drop and mean velocity was obtained, and permeability constants and drag coefficient were decided from the relationship. The experimental results were compared with two theoretical curves deriving from the cell model method, the one is for assembly of spheres and the other for assembly of circular cylinders. It was found that the observed plots were distributed in the region bounded by two curves under the condition that the volume fraction range of porous material is 0.1 to 0.6.

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Several agents named Warmth-retaining agents are mixed in the coated layers on the polyester fabrics.
The aluminum-powder or the copper-powder which retains the warmth with reflection shows greater warmth-retention when the coated layer is on the outer side of the clothes than on the inner side.
On the other hand, carbon-powder or the oxidized iron-powder shows greater warmth-retention when the coated layer is on the inner side of theclothes than on the outer side.
Electron micrographs showed clearly the various structures in the coated layers when the warmth-retaining agents are mixed in the resin.
There are the multilayers, porous layers, and/or airly layers made with the warmth-retaining agents, air, and the resin.
Basing on these structure, roles of the warmth-retaining agents are discussed.

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