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Volume 1964 (1964)
- Issue 40 Pages 2-
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- Issue 38 Pages 3-
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Volume 1964, Issue 38
Displaying 1-8 of 8 articles from this issue
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[in Japanese]1964 Volume 1964 Issue 38 Pages 3-5
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
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[in Japanese]1964 Volume 1964 Issue 38 Pages 6-8
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
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M. H. Saito, T. Tsuzuku1964 Volume 1964 Issue 38 Pages 9-14
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSBy means of an electromagnetic driving and detection technique, the effects of fatigue by cyclic straining on the low-amplitude internal friction (Q-1) as well as the dynamic modulus (E) of the two typical carbon solids, i.e. glassy hard carbon and polycrystalline graphite, have been investigated.
The glassy carbon specimens heat treated (HT) at 1000°C indicated very short life in the fatigue test, i. e., failed at about 6.5×105 cycles of straining (N) to the amplitude level of 4.5×10-4, while it looks apparently excellent in the relaxation characters, having high Q-1 and low E. In view of its high electric resistivity observed beside, such a discrepancy is concluded to come from the presence of viscoelastic organic impurities dispersed rather inhomogeneously in the texture. The 2000°C HT specimen survived the 1000°C HT one by factor of about eleven, after indicating a peak of Q-1-N curve arround N=5×105 cycles on the ordinate. The 3000°C HT epecimen was most stable never failed even after 8×107 cycle strainings.
The fatigue test for polycrystalline graphite specimens was performed at four different levels of straining amplitude from 1.2×10-4 up to 2×10-3. The character changes due to fatigue, increase of Q-1 and decline of E, were generally enhanced by raising the amplitude level. The Q-1-N curve for the level of 1.0×10-3 exhibited a peak at the nearly same position as that observed for the 2000°C HT glassy carbon.
It is pointed out that in every specimen the character changes occured mostly in the initial stage of fatigue. Brief discussions in terms of the dislocation theory are given.View full abstractDownload PDF (894K) -
Thermal Decomposition of Anthracite: Part ISeiji Kubota1964 Volume 1964 Issue 38 Pages 14-19
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn order to obtain high quality carbon powders for telephone transmitter, studies are carried out on various properties of carbon powders obtained by thermal decomposition at various temperatures in the range 700°C-1150°C in an atmosphere of nitrogen. The decomposition rate increase rapidly above 600°C, liberating large amounts of various gases, and decreases gradually above 800°C. The gases liberated at 600°C are found to be H2, N2, CH4, CO, etc. The content of H2 increasee greatly with the roasting temperature. The static resistance, response, distribution in particle size, effective area, amount of water absorbed, threshold temperature of firing and effects of mechanical and electrical shocks are studied on the carbon powders obtained at various roasting temperatures. It is found that these properties can be controlled by adjusting the roasting temperature and that the higher the temperature the more stable are the carbon powders. Textures of these powders are observed by means of electron microscope.View full abstractDownload PDF (4199K) -
Sennosuke Sato1964 Volume 1964 Issue 38 Pages 20-29
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe strengths of graphite were treated statistically by Griffith-Weibulls brittle fracture theory which led to a consistent explanation of the relation between tension and bending strength, and it was shown that the introduction of the homogeneity factor m would permit estimation of strength from data on another mode of testing. The value of m was found to range between 10 and 20, indicting a scattering of data to an extent about 4 times that of cast iron. Experiments were also conducted to determine the effect, of different mode of loading is bending test as well as of different test piece cross sections, and it. is proposed that the cross sectional form of the test peice should be standardized. The size effect on mechanical strength was determined to be proportional to the (-1/m) the power of the volume, and this relation is well supported by measured data when m is given a somewhat smaller value than that obtained fram mechanical tests.
Graphite has hitherto been utilized without confidence in its mechanical properties because of its inherent inhomogeneity, but the above discussion points toward the possibility of a better understanding of its properties through statistical treatment of the data obtained from mechanical tests made possible by the introduction of the concept of inhomogeneity factor.View full abstractDownload PDF (1349K) -
H. Kishigami, S. Mizushima1964 Volume 1964 Issue 38 Pages 29-33
Published: June 25, 1964
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSNumerical calculation has been done by means of an analogue computer to solve a non-linear partial differential equation and to obtain transient temperature distribution for the case of a graphite circular disk at the center of which heat is supplied at some given rate. It was shown to be possible to compute the distribution of temperature even when the specific heat and the thermal conductivity are functions of temperature. From the result of temperature computation thermal stresses in the disk were calculated-which are induced by the inhomogeneous temperature. In a typical case it was found that the dependence of the stress upon the position and time is quite different in the non-linear case, where the physical properties of carbon are taken to be functions of temperature, from the linear case.View full abstractDownload PDF (643K) -
1964 Volume 1964 Issue 38 Pages 34
Published: 1964
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (127K) -
1964 Volume 1964 Issue 38 Pages 40
Published: 1964
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSDownload PDF (88K)
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