All issues
Volume 12, Issue 3
Displaying 1-3 of 3 articles from this issue
- |<
- <
- 1
- >
- >|
-
Sadao Aso, Rikuhiro Kinoshita1966 Volume 12 Issue 3 Pages 101-106
Published: 1966
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSThis article presents the results of an investigation into the relation between the normal incident sound absorption coefficient and the apparent density of glass wool boards used as a sound absorbent.
(1) Only one kind of glass wool boards 64kg/m3 in apparent density and 2.5cm in thickness out of 20 kinds made by 3 manufacturers has given a sound absorption characteristic belonging to the mixed type. The sound absorption characteristics of the other kinds of glass wool boards have been shown by experiment to belong to the viscosity-resistance type.
(2) The relation between effective apparent density Dea (kg/m3) at which a glass wool board gives 1.00 in sound absorption coefficient and the thickness T (cm) is: Dea; =aT-b where a and b are constants fixed by the manufacturer.
(3) The relation among apparent density Da (kg/m3), thickness T (cm), distance d (cm) between the center of a sample and the rigid wall, and frequency f0; at which the sample gives the maximum sound absorption coefficient is expressed by the following empirical formula: f0; =(c/4-αDβa; •T)d-1 where α and β are constants and c is the speed of sound.View full abstractDownload PDF (674K) -
Part 1: Fiber Entanglement by Mason-type MachineMegumu Suzuki, Setsuko Kobayashi, Kenichi Emoto, Tsuneo Tsukada1966 Volume 12 Issue 3 Pages 107-122
Published: 1966
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSWe devised a Mason-type machine, a kind of Couette-type viscometer, and studied the buckling of fibers in the shearing field, a matter related to fiber entanglement problems, such as hooks, nep formation and pilling. We concluded that bent fibers increased in number with an increase in the viscosity of liquid.
We studied what bearing the roughness degree of the cylinder surface had on fiber entanglement. With the cylinders finished at degree W, slivers disordered and buckled fibers increased in number.
We were able to see the process of slivers buckling and forming fiber assemblies when emery paper was stuck on the cylinder surface. We found that two fiber balls in a row merged easily into a larger ball.
We attached ordinary cloth wires or metallic wires to the cylinders and thought of it as a service carding machine because of its dynamic similarity. We observed nep formation by varying the sliver density and the number of cylinder revolutions. More neps formed with an increase in the sliver density. The larger the number of cylinder revolutions, the smaller the rate of nep formation per revolution.
The mechanism of nep formation, in our opinion, consists of the buckling of slivers and the tightening of buckled slivers. The larger the number of fibers sinking among wires, the larger the number of neps forming. We were able to explain nep formation and disappearance by the rate process theory.View full abstractDownload PDF (3131K) -
Part 3: Experiments on Characteristics of Apparent UnevennessKen Kazama1966 Volume 12 Issue 3 Pages 123-132
Published: 1966
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSObject: This article experimentally reviews the assumptions on theory and the theoretical equations presented in the previous instalments. It seeks to confirm the theories previously deduced and grasp the characteristics of apparent unevenness. The samples used are 30s spun rayon yarns.
Results: 1. The over-level ratio introduced in part 1 will do as a measure, or yardstick, by which to indicate the perception of apparent unevenness.
2. Apparent unevenness is characterized not by a certain level or expression, but by the curve of the over-level ratio proper.
3. The theoretical equations derived in part 1 are practical.
4. The value of the length distribution in an ideal yarn and the value of the length distribution in service yarn have similar density functions.
5. Level, the number of uneven areas, and the relation between these two factors and length have been experimentally obtained. The mean length of uneven areas has been deduced.
6. An apparent uneven area is determined by the over-level ratio of the area proper. It is not influenced by the unevenness of environs or by the dimensions of the uneven area, i.e., not by any disturbances.
7. The over-level ratio which distinguishes an uneven area from an even area exists in each level. The value of this discrimination threshold range has been obtained.
8. The theoretical equation of the total length of uneven areas on a black board, given in part 2, fits practical cases.View full abstractDownload PDF (1503K)
- |<
- <
- 1
- >
- >|