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Volume 11, Issue 3
Displaying 1-5 of 5 articles from this issue
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Sadao Aso, Rikuhiro Kinoshita1965 Volume 11 Issue 3 Pages 81-87
Published: 1965
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSTo determine the most suitable porosity of a fiber assembly used as a sound absorbent, we measured the sound absorption coefficients of fiber assemblies having air spaces behind them by the standing wave method and investigated their sound absorption characteristics. The results:
(1) Sound absorption characteristics change from a viscosity-resistance type to, successively, a mixed type and a resonance type as they decrease in porosity. There are two types of absorption characteristics of the resonance type. One is a fibrous resonance type, which is for a thick sample. The other is a board resonance, for a thin sample.
(2) The relation between the most suitable porosity Pe; (%) at which a fiber assembly has the maximum sound absorption, i.e., 1.00, and the thickness T (cm) is shown as follows: (100-Pe; )=a'T-b' where a' is a constant which is decided by fiber fineness and b' is another constant. If T is constant, the relation between Pe; and fiber fineness d (denier) is shown as follows: (100-Pe; )d1/2=C where C is a constant decided by T.
(3) The relation between the total surface area S (cm2) of fibers constituting a fiber assembly of porosity Pe; (%) and T (cm) is shown as follows: S=aTb×104 where a and b are constants.
A fiber assembly which meets this equation has the maximum sound absorption coefficient at a certain frequency, if it has no back air space, or at an optional frequency if it has a back air space suited to the frequency.View full abstractDownload PDF (962K) -
Part 3: Economic BalanceHisao Kono1965 Volume 11 Issue 3 Pages 88-93
Published: 1965
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSWe have calculated plant economy by using the results published previously and by deducing eight equations which determine eight variables necessary for designing an acetylator.
The eight variables are: Optimum thickness of the fiber layer w [kg/m2] Optimum velocity of the reactant gas flowing across the fiber layer v [m/min] Drop in gas pressure needed for circulationΔP [kg/m2] Concentration of acetic anhydride in the acetylator cr1 [kg/m3] Reaction time θr; [min] Volume of reactant gas supplied F [m3/kg*] Volume of reactant gas reclaimed D [m3/kg*] Effective area of reaction surface Ar; [m2]
Eight equations have been obtained as follows: From the results given in the previous articles or their deviations, θr; =α1; /cr1;, α1; =mMr; 1/m/KC eq. (3) v=β1; w, β1; =(0.415 ρg; ; /ΔM)1/1.36/ρg; or ={561/(tf; -tg; )}1/1.22/ρg; eq. (11) Using whichever β1; is larger in value of the two J=Ar; w'/θr; =Ar; w'cr1; /∂1; eq. (4) ΔP=β2; w1.42 v1.48+β3; v2 eq. (13) From the material balance in the acetylator D=K1; -a(K1; -K2; )/cr; (a-b) eq. (5) F=K1; -b(K1; -K2; )/CF; (a-b) eq. (6) Equations of economy are derived from the above results: b=(α2; -√<α2; α3; >/α2; β3; )a eq. (8) 2.90 β1; 2.48 β2; w3.9+2β1; 3β3; w3=6120ηYr; γ/1.47 E(f1; +f2;) eq. (11) Symbols are so numerous the readers are requested to refer to the text. These equations determine the values of variables needed for designing an acetylator.View full abstractDownload PDF (758K) -
Fusakichi Nakagawa, Yasushi Kobayashi1965 Volume 11 Issue 3 Pages 94-99
Published: 1965
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSDownload PDF (1045K) -
Part 2: Theory on the Apparent Unevenness on the Black BoardKen Kazama1965 Volume 11 Issue 3 Pages 100-107
Published: 1965
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSObject The relation between the apparent unevenness of a spun yarn and the apparent unevenness on the black board is discussed theoretically. The apparent unevenness on the black board is expressed by the total length of its various widths. Results
1. The probability of the presence of uneven areas exceeding m in number in a band made of infinitely long, parallel yarns to the number of M is given as: P(_??_m, M)=1-∑<m-1><i=0> (M i)(α/β)i/(1+α/β)M, where α is the input density and β the output density of an uneven area in a yarn.
2. The total length T of apparent uneven areas shown on a black board which has widths to the number of N and which is L in length is obtained as follows: T=L(N-M+1)[P(_??_m, M)-∑<m-1><j=1>P(_??_m, M-j)-{P(_??_m', M+1)-∑<M><j=1>p(_??_m', M+1-j)}]where m is the discrimination threshold for an uneven area having widths to the number of M, and m' is the discrimination threshold for widths to the number of M+1.
3. The total length T of apparent uneven areas in ideal yarns and the total length T of service yarns Nos. 1 and 3 are calculated by using the foregoing results.
4. The length distribution of apparent uneven areas is the transition probability of a high order in Markov's chain.View full abstractDownload PDF (979K) -
N. Inui, M. Kurata1965 Volume 11 Issue 3 Pages 108-118
Published: 1965
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSObject: The reasons behind the formation of thick-and-thin places on cloth have been investigated, preliminary to developing a new type of let-off motion simple in mechanism, yet as efficient as a completely automatic positive let-off motion. The results obtained have given birth to a highly efficiency let-off motion of simplified mechanism.
Results: (1) Variations in maximum tension have an important bearing on the formation of thick-and-thin places. Thick-and-thin places are avoided if the tension curve of variations in maximum tension per cycle during long-time weaving is close to the horizontal.
(2) With the tension roller in good working condition, intermittent surplus let-off produces no thick-and-thin places.
(3) The frictional resistance of shafts which is related to the tension roller parts influences the working of the tension roller measurably. The use of ball-bearings in these parts is beneficial.
(4) If a tension device having smooth-working tension roller is used, the presence or absence of an easing motion has hardly any influence on the formation of thick-and-thin places.View full abstractDownload PDF (1218K)
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