This work invesigates the two-dimensional fiber orientation in a recirculating flow within a salient corner of an abrupt expansion channel in order to elucidate the fiber orientation state in a recirculating flow as a fundamental study on anisotropic channel flow.
Orientation of a large number of fibers (N=1, 800) with aspect ratio r_a = 5 and 100, which are injected with a random initial orientation, can be evaluated by computing the Jeffery's equation along two streamlines. Then, the second-order orientation tensor and orientation ellipse, which are suitable and concise ways of describing the orientation distribution of fibers, can be determined using this statistical scheme. The effects of aspect-ratio of fibers and location of streamlines along which fibers circulate on the evolution of the second-order orientation tensor and the orientation ellipse are discussed in detail. Furthermore, orientation visualization experiments of large aspect-ratio fibers were carried out in a recirculating flow which occurs within a salient corner of a backward-facing step channel, and the observed fiber orientations are compared with the computed ones.
For large aspect-ratio fibers, steady orientation state of fibers can be obtained after several circulation, and furthermore, all fibers almost completely align along the streamlines. This result is obseved in both the experiments and computations.
On the other hand, the computations predict that for small aspect-ratio fibers, steady and almost complete orientation state can be observed along streamlines, however, preferred angle of fibers lies obliquely to the streamlines even in such an orientation state.
Therefore, fiber suspension flows through a complex channel, where recirculating flows occur, can be rigorously computed by taking account of fiber orientation distribution as follows :
(1) Fiber orientation distribution has to be computed in a main flow regime.
(2) In a recirculating flow regime, large aspect-ratio fibers completely align along the streamlines. On the otherhand, for small aspect-ratio fibers, steady and complete orientation state can also be attained, however, preferred angle of fibers has to be computed.

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In order to disclose the dissolved state of cellulose in cuprammonium solution in semi-dilute regime, we investigated the viscosity, the complex structure of the solution with various cellulose and ammonia concentrations, and, degree of polymerization of the cellulose.
The results are as follows : (1) The cellulose cuprammonium solution shows Newtonian nature at relatively low shear rate r (r< 1). (2) The solution viscosity at zero shear rate no is proportional to the 3.3 power of the degree of polymerization of cellulose and to the 4.4-4.9 power of the cellulose concentration. (3) The increase of the weight ratio of ammonia to cellulose as a glucose unit (NH₃/Cell) brings about the lowering of ηo. The rate of the decrease slightly changes at specific NH₃/Cell value and the structure of complex drastically changes at the point.

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A high performance yarn speedometer adopting optical correlation method has been developed to contribute to efficient improvement of looms.
Among some velocity measuring methods, optical correlation method is the most suitable for a yarn intense speedometer because of its high accuracy and simple equipment composition.
Optical characteristics of spinning yarn and filament yarn were investigated for the development.
The investigation of frequency characteristics revealed that transmitted light intense signals for both the yarns were roughly random, which indicates optical correlation method was suitable for velocity measurement.
Measuring accuracy of a trial manufacture yarn speedometer was checked by measuring the velocity of the yarn which moved at a constant velocity.
The influence of the structural factors of the trial yarn speedometer on the accuracy was also examined.
Based on the above result, the trial yarn speedometer was adjusted optimallyand the yarn velocity near the main nozzle of air jet loom was measured.
The measuring accuracy of the adjusted speedometer was found comparable to that of laser Doppler velocimeter.

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Double covered yarn is produced by an double covering machine equipped with hundreds pairs of upper and lower hollow spindles. Drawing Spandex to be a core yarn of covered yarn into the hollow spindles is so complicated that its automation is especially hoped. So we developed an auto drawing-in apparatus that could draw Spandex in both upper and lower hollow spindles simultaneously. Results obtained are as follows :
(1) The auto drawing-in apparatus comprises both an injector and an ejector. Spandex was drawn into the lower spindle by the injection flow driven by the injector and was drawn from the upper spindle by the suction flow driven by the ejector.
(2) Drawing-in was performed for a model covering machine by the developed auto-doffing apparatus. It could draw-in 20D Spandex that was widely used and was too thin to be easily drawn-in even by a manual doffing operation. So this confirmed that the developed auto-doffing apparatus had practical utility in drawing -in operation .
(3) The rates of success of Spandex drawing-in is influenced by the supplied air pressure for the injector, the supplied air pressure for the ejector and the feed rate of Spandex. High certainty of Spandex drawing-in could be accomplished by the proper arrangement of those conditions.

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