Rotary bending strength of nodular cast iron pipes (outside diameter 23mm, thickness 1.5mm) with a radial hole of various diameters was measured. Their notch-factors (factors of stress concentration in fatigue) were found to be very small. In this material fatigue crack spreads along a line connection the nodular graphites. From the point of view that fatigue crack develops at the root of a notch when small part near the root is stressed above the fatigue limit of the material the relation between form-factors (factors of stress concentration in elasticity) and the notch-factors was discussed. Notch effects of nodular graphite itself in connection with machined one was also discussed.

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Crazing (fire cracking) occurs on the high temperature surfaces of metallic materials that are heated to high temperature repeatedly. About this phenomenon, various explanations have been published.
Author threw light on its mechanism by calculating the change of stress and strain on the inner surface of 5 ton ingot mould during steel ingot making operation.
Result obtained is as follows; the mechanism of crazing phenomenon is based on repeated stress-compressive stress on heating period, tensile stress on cooling period and residual tensile stress after cooling-which appears on the high temperature surface of the materials.

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In this paper discussed neccessity of paper thickness measurements and introduced several electric thickness meters, static capacity method, electromagnetic method.
In the next place, described the principle, construction and characteristics of ETL type meter by electromagnetic induction method.
By practical experiment this method are discoverd that can be continuous recording and nondestructive indication.

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On the compression test of a log laid horizontally, the log breaks from the centre of the log by the small load, and this crack extends vertically. Hitherto, on the design of the bolsters of wooden bridge, we adopted practically larger sectional area, than that obtained by bending and bearing stress calculations. Author proposes in this paper, that stress of tear by compression must also be considered on that reasonable design.

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This paper describes a tensile creep testing machine of 1 ton capacity and some test results by use of it. The machine was provided about 10 years ago. It is nothing but an ordinary one or K. W. I. type and has no feature, excepting that a suitable counter-plan is considered on the temperature variations and fluctuations of a test specimen.
Some test results on steels suggest that the machine would well be useful for a short term creep test.

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New impact tensile tester for single fiber was devised. Its faculty and test method were discussed in detail. Using this tester, the values of impact rupture energy of various natural, rayon and synthetic fibers were estimated. The values for cotton and ramie are the lowest (1.7∼2.0erg/cm³), next to them are wool and various celltilosic rayon (3.7∼1.7×10⁸erg/cm³). Various synthetic fibers have higer values in general (5.5∼11.6×10⁸erg/cm³). In the wet state the energy value for cotton is not affected, but for ramie, silk and viscose rayon they are decreased remarkably. The effect of the degree of polymerisation was examined with vinylon and nylon. The energy values were lowered with the decrease of the degree of polymerisation.

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