Described in this paper is a soil moisture determination applying the neutron diffusion method. As a result of examining the cause of measuring error of the moisture meter, it was proved that the error due to the difference of soil components is within 0.02kg/l, the error due to the change of bulk density of samples is negligible and the effect of sample volume is observed especially in dry samples. Given as actual examples are sand moisture measurement at a concrete batcher plant and calorie measurement of crude petroleum.

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Studied is a method of realization of blackbody radiation at the gold point, which has such experimental conveniences as sighting can be made from horizontal direction without any intermediate optical system and as correctness of the sighting can be easily verified.
It was confirmed that the radiation observed by a precision micro-optical pyrometer sighted to this radiator can be identified within the limit of ±0.1 deg. with that of a perfect blackbody radiator at the gold point.
Described in this paper are the devices and operations found suitable for this method as well as experimental and theoretical proofs made by the author to ascertain whether or not the above devices and operations are adequate.

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Bourdon-tube gauges very often go wrong when used for dynamic pressure measurement. As its reason, it was assumed that impact of movement gears, sector and pinion, would damage the teeth surfaces.
Maximum impact stress σmax was calculated applying Hertzs theory. σmax varies with vibrating condition, bearing clearance, gear size and inertia moment, and often becomes larger than allowable stress of gear material when a long pointer is used. Large bearing clearance also results in too large σmax.

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Magnetic hysteresis phenomena present unique characteristics as compared with other hysteresis phenomena such as heredity and backlash. Since no attempt to make an analog simulator for magnetic characteristics and to apply it as a computing element of an analog computer has ever been reported, it is exceedingly difficult at present to analyze the system that involves such hysteresis characteristics as presented by magnetism.
The author has presented a theory that magnetic hysteresis characteristics can be simulated by a group of irreversible switches.1) Based upon this theory, a simulator or function generatar has been built with satisfactory performance characteristics. The main part of the function generator consists of 50 each of electronic trigger circuits and mechanical relays. The generator works satisfactorily up to a repeating frequency of nearly 10 cps with an overall accuracy of about 1%. By turning a variable resistor by means of a knob on the panel of the generator, the form of hysteresis curves can be changed arbitrarily.
The function generator will also work efficiently as a computing element of a conventional low speed analog computer. Given as its application examples are the response of a control system involving hysteresis characteristics and the result of analysis of the saturable reactor circuit accompanied with a jumping phenomenon.

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