The rolling stock and its accessories as well as materials used by the Japanese Goverment Raiiways are under gradual improvement. The author summarizes briefly the matters investigated in connection with the improvement, such as the increases of tensile strength of wheel tyres, the improvement in material for brake shoes, the increase of carbon content in spring steel and the reduction of allowable stresses, the application of "Niseko" steel, the improvement of home made asbestos sheet packings, the steam leakage from piston packings, the experience in using vanadium steel, the durability of pressure gauges, the use of potassium-bichromate and soda-ash as a cleanser for locomotive boilers, the improvement in design of steel carriages, the utilization of copper-bearing steel, the investigation for painting passenger cars, the experiment for ventilators of passenger cars, the improvement of diaphragms for automatic regulators for steam heater of cars, the arrangement for giving humidity in passenger cars, the investigation for heat insulating materials, the construction of refrigerating cars, the effect of shapes of car ends upon the air resistance, the improvement of rheostat for electric cars and electric locomotives, the appliances for the prevention of noise in passenger cars and electric cars, the improvement of circuit-breakers, the investigation for pneumatic whistles and the research on carbon brushes for electric trains.

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The present paper introduces the outline of the design of Japanese-home standard motor cars selected by the Investigation Committee for the Establishment of Automobile Industry in Japan, and also explains the reason for the determination of design and the general principle. The author desires that this paper will be read in connection with Dr. Takemura's paper "On nationalized standard Motor Cars, " published in this journal of May, 1932.

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The paper refers to a new consideration for a method causing vortex motion of air in the cylinder of an internal combustion engine by utilizing the reciprocating motion of the piston, and states that vortices can be produced well by letting air dash into the cylinder at a high speed in outward stroke from a hollow made in the piston or in the cylinder cover.

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In order to cut off injection oil at open nozzles without dripping, the fuel oil pressure must suddenly drop down to a pressure lower than that in the cylinder. In this paper the effect of the size of oil pipes, the shape and position of delivery valves upon the pressure drop was examined. Some experiments were carried out for oil pipes of usual sizes with a view of confirming the previous examination.

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This is a report for an experimental research in comparison with the effect of differences in the broadness of the passage of the guide vane, its shape, the outlet angle etc. upon the characteristic of a centrifugal pump. In case that a pump is worked with an impeller combined with various guide vanes, the experimental results clearly show that the exit angle of guide vanes and the degree of expansion of passages have a close connection with the characteristic of a pump, but amongst them the size of inlet area of the passage is the most influencial factor for the efficiency and the lift of the pump. Calculating the velocity of flow at the entrance of the guide vane passage and the absolute velocity at the outlet of the impeller for various lifting capacities, and examining the condition of velocity variation in connection with these factors, the existence of a very close connection between these factors and the pump efficiency can be recognized.

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This report deals with the results of torsion test carried out instantaneously by a newly designed impulsive torsion tester. For the twisting moment, the twist of a spring was utilized and M-θ curves of the impulsive torsion were taken in photographs. The results of breaking cylindrical test pieces of annealed mild steel and copper by changing the speed, and M-θ curves at various shapes of notched test pieces of mild steel are statically compared. Further, applying Ludwick's theory and from twisting M-θ curves, the problem on the general variation of the slipping resistance at the deformation of materials in accordance with the speed has been solved.

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When temperatures T_1 and T_2 at internal and external surfaces of a hollow cube are given, the coefficients necessary for obtaining the heat quantity transmitted between them were acquired by electric tank experiments. This problem was also dealt with briefly in the author's paper read before the Joint Meeting for the Advancement of Applied Mechanics, October 1931 and an approximate method was given therein, but its application was limited to the momentary object. The present paper is a report concerning results due to the correct method carried out thence and shows that the difference in comparison with coefficients obtained and those hitherto used was more than 10%, even within a practical scope.

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In discussing the solution of standard expression assuming the heat capacity as a constant and the heat conductivity as a function of temperature, Van Dusen's solution assuming the temperature transmission rate as a constant and the heat conductivity as a function of temperature is also discussed. Further, the solution of basic expression for a body of gradually varying material as an infinite or a semi-infinite body is dealt with and a solution as a homogeneous body is induced.

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A beam with a section formed by two concentric circles and two radii, i.e. a pipe with a longitudinal groove at one side parallel to the axis was fixed at one end and loaded at the other end. The shearing stresses were classified into two kinds, one as a function of the flexure and the other as a function of the twisting, and it was concluded that the effect of the latter is very large when the thickness is small.

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This report deals with an example of solutions for stresses of a rectangular plate under uniformly distributed load, two opposite sides of which are placed freely on strong supports and the remaining two sides on elastic beams, and the calculated results were confirmed by experiments.

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[in Japanese]

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