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Volume 42, Issue 3
Displaying 1-11 of 11 articles from this issue
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KATSUHIKO NAKAMAE1986 Volume 42 Issue 3 Pages P67-P72
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
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KAORU SHIMAMURA, FUMIYOSHI YOKOYAMA1986 Volume 42 Issue 3 Pages P73-P81
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
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SUEO KAWABATA1986 Volume 42 Issue 3 Pages P82-P89
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
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Norihiro Kaiya, Masahiro Kugishima, Atsushi Takahara, Tisato Kajiyama1986 Volume 42 Issue 3 Pages T127-T135
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe fatigue behavior of solid-state extruded high-density polyethylene (HDPE) was investigated on the basis of dynamic viscoelastic measurements during the fatigue process. It was observed that the fatigue lifetime at a certain imposed strain amplitude decreased with an increase in extrusion ratio. On the other hand, the fatigue lifetime at a certain stress amplitude increased with extrusion ratio. This may be due to an increase in modulus with extrusion ratio. The difference in fatigue fracture behavior between the unextrudate and extrudate was investigated in consideration of their higher order structure. In the case of the unextrudate, the fatigue fracture took place perpendicular to the direction of cyclic straining. On the other hand, in the case of the extrudate, fatigue fracture took place after the formation of kink bands which inclined by ca. 45 degree to the extruding direction. The variations of dynamic viscoelasticity during the fatigue process were measured for the extrudate and unextrudate. The maximum of E′ and the minimum of tan δ on approaching the point of failure were observed for the unextrudate under small imposed strain amplitude. This indicated the orientation of molecular chains under cyclic straining. Otherwise, such viscoelastic behaviors could not be observed for the extrudate. This can be attributed to the prior existed highly oriented molecular chains in the extrudate. The fatigue criterion based on hysteresis loss was established for the unextrudate and extrudate, respectively. The total hysteresis loss up to fatigue failure for the extrudate was larger than that for the unextrudate.View full abstractDownload PDF (1976K) -
PART I. MOISTURE SORPTION AND DESORPTION ISOTHERMS OF CELLULOSIC FIBERSKazunori Kohata, Mariko Miyagawa, Akira Takaoka, Hiromichi Kawai1986 Volume 42 Issue 3 Pages T136-T154
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSTwelve kinds of cellulosic fiber, including natural, regenerated, and chemically modified fibers, were prepared for measuring the moisture sorption and desorption isotherms at various temperatures from 10 to 50°C by two types of gravimetric method, a weighing bottle method and a sorption balance method with quartz spring in vacuum.
From the temperature dependence of the sorption isotherm, the excess energy (entropy term) of moisture sorption on the cellulose fiber was found, on the basis of thermodynamics, to be the largest in dry state ranging up to ca. 100cal/gr of liquid water, and to decrease rapidly down to almost zero with increasing relative humidity up to saturation, suggesting that the sorbed water is in a very ordered state, like in crystal lattice of ice, at the dryness, and is still in somewhat more ordered state than in the liquid state even near the saturation.
The sorption isotherms of the various kinds of cellulosic fiber at 30°C were analyzed by the Brunauer, Emmett, and Teller's (BET) multilayer adsorption model to discuss the nature of the sorbed water in terms of the BET parameters, νm, C, and nmax; maximum volume of unilayeredadsorbed water per gram of dry material, adsorptive energy factor, and a maximum number of adsorbed layers below which the calculated moisture sorption never exceeds the experimental result. The nmax was found to be 6 for almost every cellulosic fiber with a few exceptions of 4 for triacetate rayon and of 7 for a Na-carboxymethylated rayon. The natures of adsorbed waters with n=1 (Langmuir's unilayered), with nmax_??_n>1 (multilayered), and with n>nmax, were examined in comparison with a molecular spectroscopic analysis by a proton broadline NMR, revealing that the waters with n_??_(nmax -1) and (nmax -1)>n correspond to relatively weakly and strongly interacted waters with adsorbent, respectively, though the weakly interacted water being still not assigned to the so-called free water as comparable to bulk water.View full abstractDownload PDF (1921K) -
PART 1. A SIMULATION BY VERTICAL CYLINDERYoshinobu Kamata, Toyofumi Kato, Hiromitsu Azumi, Shinji Watanabe1986 Volume 42 Issue 3 Pages T155-T162
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSConvective heat transfer from human body was studied from a standpoint of heat transfer engineering.
By using a cylindrical heat source set up vertically in a wind tunnel, an experimental formula that predicted convective heat transfer coefficient which was applicable to both forced and natural convections was proposed. When air velocity is high, this formula agrees well with that proposed by Douglas and Churchill in the region of forced convection. By using this formula we derived another useful formula which determined convective heat transfer coefficient for human body as a function of air velocity, diameter of human body and temperature difference between the body and surrounding air. It was found that the coefficients increased rapidly with increasing air velocity. Furthermore, the coefficients decreased with increasing diameter of human body and their rate of decrease became smaller with the increase of diameter.View full abstractDownload PDF (422K) -
Satoshi Mashimo, Kazuhiro Takeda, Takashi Kinoshita, Yoshio Yamaguchi, ...1986 Volume 42 Issue 3 Pages T163-T168
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe change in structure of the stretched and heat set PET cord and the PET cord-rubber composite was discussed by means of the results of load-extension and stress relaxation measurements.
Test specimens were the PET cords treated under stretching ratio (L/L0) of 1.04-1.10 and heat set temperature of 200°C-240°C (=sample A), the composite consisting of sample A and the polychloroprene rubber matrix (=sample B), and the cord picked up from the sample B (=sample C).
The relaxation modulus of sample A and sample B increased with increasing heat set temperature and stretching ratio. In the cases of much higher stretching ratios, the relaxation modulus of sample A decreased with stretching ratio. The relaxation modulus of sample B was higher than that of sample A.
From these results, the stretching and heat set of the cords seems to create defects by the rearrangement of molecular chains. These behavior tend to be remarkable under the heat treatment condition of lower heat set temperature and higher stretching ratio. The number of defects seems to decrease with heat treatment by curing.View full abstractDownload PDF (870K) -
Taisuke Ito, Jiro Seta1986 Volume 42 Issue 3 Pages T169-T176
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe volume occupied by a molecule was defined in two different ways: one, denoted by Vnet, is the net volume for the van der Waals' contact model for the molecule which was constructed by the use of the bond lengths, the bond angles and the van der Waals' radii of the constituent atoms, and the other, Vcry., is the mean volume occupied by the molecule in the crystalline state.
A program was developed to give an accurate estimation of Vnet in which the number of a small cell having a volume increment of ΔxΔyΔz was computed within the range inside the van der Waals' contact model. The Vnet calculated in this way was denoted by Vlp.. Calculations of Vlp. were carried out for 12 azo and 6 anthraquinone compounds and the results were compared with the values of VKi. and VEd. which were obtained according to Kitaigorodskii's and Edward's methods, respectively. In these two methods, the volume increments specified to the atom or atomic group were summed up along the whole molecule. In spite that VKi. (and VEd.) neglects the overlapping of the van der Waals' contact spheres between nonbonded atoms within a molecule, it was surprising to find that VKi. showed a good agreement with Vlp. respecting to the above aromatic molecules. VEd. gave values several % smaller than Vlp.
Vcry. can be experimentally determined by density measurement (Vρ). It can also be calculated from the unit cell volume and the number of the molecules in the cell (VX). For flat molecules such as those examined in the present study, it was found that Vcry. can be predicted well from the area of the silhouette of the van der Waals' model multiplied by a “thickness” This thickness was determined by a least squares fit so as to give VW (=silhouette area×thickness)=VX where some twenty typical aromatic compounds having known X-ray data were considered. Good agreement was found between VW and Vρ for the aromatic molecules examined in this study.
Finally, the packing density K in the crystalline state, given by K=Vnet/VX, was also discussed.View full abstractDownload PDF (554K) -
Yasushi Takano, Yasushi Nakajima, Mituo Arai, Kenji Okuyama, Kiyoshi H ...1986 Volume 42 Issue 3 Pages T177-T181
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIt has been reported that silk fibroin in an air-dry state has three mechanical loss peaks at -120°C, -50°C and 230°C over the temperature range -150° and 300°C. They are referred to as γ, β and α relaxation, respectively. Mechanism of the β-relaxation, however, is not fully clarified, although it may be attributed to some motion concerned with adsorbed water because of the fact that the peak temperature of relaxation varies from -100°C to 0°C with water content.
In order to obtain further information on the β-relaxation, model compounds having serine side chain were synthesized. These compounds are copolymers of acrylonitrile and allyl alcohol, and these partially hydrolysed products. Dynamic mechanical relaxation of model compounds as well as the sericin were measured.
The β-relaxation peak in both the model compounds and the sericin was observed in only the case that serine side chain, hydrogen bonding sites and water are all present. Furthermore, the β-relaxation of the model compound shifts to lower temperature with increasing water content.
These results possibly show that the mechanisms of the β-relaxation of the model compound and silk fibroin are same, and finally lead to the assumption that the β-relaxation is attributed to the cooperative molecular oscillation among the serine side chain, hydrogen bonding sites and water.View full abstractDownload PDF (335K) -
Yasuhiko Nukushina, Junichi Matsui, Motoi Itoh1986 Volume 42 Issue 3 Pages T182-T187
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSCarbon fiber is a material with high elastic modulus and very low strain at failure. In this paper a precise strain measuring equipment and its application to carbon fiber are presented. The equipment is composed of a tensile tester, an optical mark detector and a length measuring device. The measuring technique is the same as for measuring changes of gauge length by loading weights with a cathetometer. A high strength and high modulus carbon fiber, Torayca T300, is evaluated with a specimen which is prepared by impregnating the yarn in epoxy resin and then curing in the form of a thin bar. Carbon fiber behaves as an elastic body and has no plastic deformation. Nonlinear stress to strain response and stress-induced stiffening effects are observed. The elastic modulus increases proportionally with the strain.View full abstractDownload PDF (916K) -
Eiji Toba, Norimasa Fujimoto, Sadamu Sekiguchi1986 Volume 42 Issue 3 Pages T188-T191
Published: March 10, 1986
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSAn attempt was made to apply single-mode optical fibers to distortion sensors.
When the single-mode optical fiber was subjected to the distortion difference, the fiber length, the index of refraction and the core diameter changed as a function of distortion, and accordingly optical phase shifts were observed.
Optical phase shift was evaluated using the automatic phase shift detector of the Mach-Zehnder fiber interferometer type fabricated at our laboratory to detect fringe shifts.
The sensitivity of distortion obtained by using this device was in good agreement with the calculated values. Therefore, the single-mode optical fiber can be utilized as a distortion sensor.View full abstractDownload PDF (215K)
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