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Yuzo NAKAGAWA
1959 Volume 2 Issue 8 Pages
501-503
Published: 1959
Released on J-STAGE: February 15, 2008
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It is now recognized as a well-known fact that the yield point depends on the rate of strain as a result of the investigations by Ludwik, Manjoine and other investigators. The author presents a new theory in order to explain this phenomenon and expresses it by a model which consists of two springs, two dashpots and one friction block. The arrangement of these component parts in this model is somewhat different from any other model used widely in the field of rheology. The relation among the stress, the strain and the rate of strain is expressed by the following equations in this theory : σ=Eε
6+Bε^^·
p and Eε
6=D+Bε^^·
p where σ means the stress, ε
e, the elastic strain, ε^^·
p, the rate of strain and D is the force acting on the friction block..
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Yasuo SATO
1959 Volume 2 Issue 8 Pages
504-508
Published: 1959
Released on J-STAGE: February 15, 2008
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According to the experiments on the yield point of mild steel cylinders under internal pressure, pressure-strain relations beyond the yield points take two different modes : - In the range of γ < 1.55, where γ is the ratio of the outer to the inner diameter of the cylinder, the strain increases under a constant pressure at the yield point Y, while in the range of γ > 1.55, the strain increases with pressure even after the yield point Y', and reaches a certain point Y at which it behaves in the similar manner to the former case (Fig. 2). F. Nakanishi has proposed a new theory on the yield point of mild steel and the experimental results have justified his theory, concerning the relation between pressure and strain as well as the stress at the yield point throughout all the range of γ.
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Shuji TAIRA, Ryoichi KOTERAZAWA, Mutsuo INOUE
1959 Volume 2 Issue 8 Pages
508-513
Published: 1959
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The fatigue and dynamic creep tests were made under the simulated service condition of turbine blades, i.e. combined stresses of static tension and alternating bending at an elevated temperature of 450°C. The frequency of alternating bending stress was 780 c.p.m. and the test period was 0.2 to 200 hours. The results are summarized as follows : 1. Alternating bending stress superimposed on static tensile stress reduces the fatigue life. 2. Alternating bending stress which is combined with static tensile stress does not always increases creep strain. In the range of small stress ratio (alternating bending stress divided by static stress) alternating bending stress blocks the increase in creep strain. 3. The hindrance of increase in creep strain by alternating bending stress is explained by the hardening effect of materials by stress alternation.
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Shuji TAIRA, Kichinosuke TANAKA, Kiyotsugu OHJI, Isao HARUMOTO
1959 Volume 2 Issue 8 Pages
514-520
Published: 1959
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Creep tests were made with 0.14 percent carbon steel at 450°C under periodic stresses, changing stepwise between two stress levels, the mean of which was 17.0 kg/mm
2 and the stress amplitude of which was 1.0 or 2.0 kg/mm
2. It was found that, under the test conditions in this study, creep strain under varying stresses could be predicted from the data of constant stress creep tests by applying the concept of the "mechanical equation of state in solid"with an error not exceeding 10 percent. The limitations of the "mechanical equation of state"as a practical method of estimation of the strain under varying stresses were discussed on the basis of the authors' theory of plastic deformation of metals at high temperatures, in which the effect of stress and temperature history was taken into account.
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Minoru HAMADA
1959 Volume 2 Issue 8 Pages
520-526
Published: 1959
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Buckling problems of a rhomboidal plate with all edges clamped, on which compressive or shearing force is applied along its edges, are studied in this paper by using the energy method (Lagrangian multiplier method). Natural vibrations of the plate are also considered. The lowest buckling loads and the fundamental frequencies for several oblique angles are calculated. Convergency of the solutions is considered good enough.
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Shoichi KONISHI, Hiroshi NAKAMURA
1959 Volume 2 Issue 8 Pages
526-532
Published: 1959
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An experimental test of the loads on the wheel passing a curved track, -lateral, vertical, and longitudinal loads, -was carried out for the new B-B-B diesel electric locomotive of type DF 50. The results are as follows : 1) Lateral load : For the leading axle, the lateral loads act from outside towards center of the wheelset for both wheels. As for the inside wheel, the load is nearly independent of the curvature of track, while, for the outer one, it increases as the radius of curve diminishes, attaining a max. value of 5.6 tons (Lateral load/Vertical load=0.7) for 200 m. radius. On the other hand, for the trailing axle, the loads are very small with indefinite directions of action. 2) Vertical load : The vertical loads generally agree with the theoretical values, calculated considering the centrifugal force. 3) Longitudinal load : While the longitudinal load has been hitherto rarely treated theoretically, considerable loads were revealed, attaining a max. value of 1.9 tons. The direction of loads is forward for the outer wheel of the leading axle and the inside wheel of the trailing one, and backward for the remainder.
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Syusuke IIDA
1959 Volume 2 Issue 8 Pages
532-537
Published: 1959
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The critical speed of a shaft rotating in fluid is different from that in vacuum. In this paper the effects of fluid upon the critical speed of a shaft rotating in a casing are calculated and compared with the experimental results. Also, taking the gyroscopic effects into consideration, the frequency of the shaft is calculated.
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Kosaku IIDA, Akio IGARASHI
1959 Volume 2 Issue 8 Pages
538-545
Published: 1959
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It has been considered that each roller in a cylindrical roller bearing performs both 2-dimensional planetary motion (i.e. rotation and revolution), and 3-dimensional skewing action. This behaviour, along with many other factors, affect the bearing characteristics such as running noise, friction and etc. To study the relations between roller motion and such characteristics, rotation and revolution of rollers are observed and photographed by stroboscope. In case of comparatively large radial clearance, a roller in the unloaded zone travels being guided by the raceway of outer race and retainer pocket and continues to decrease its rotational speed until it comes into the loaded zone. This behaviour of the roller can be explained by the theory introduced in this paper. For a small or negative radial clearance, rotation and revolution of each roller is always in good agreement with the conventional theory since there is no slip between rollers and races.
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Mitsuru TOYOGUCHI, Yoshiro TAKAI
1959 Volume 2 Issue 8 Pages
545-550
Published: 1959
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In this article, effect of E.P. additives on the load carrying capacity by I.A.E. type machine, was discussed and compared with results obtained by Timken and Soda four ball machine. Then commercial mild E.P. and E.P. type gear oils in Japan were tested by these testers. It was found that it was possible to use I.A.E. type machine for evaluation of load carrying capacity of mild E.P. type gear oil but not for E.P. type one.
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Tetsu FUJII
1959 Volume 2 Issue 8 Pages
551-555
Published: 1959
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The free convection boundary layers of ethyleneglycol or water along a vertical cylinder are observed. A laminar layer transits to a vortex street layer at G
rP
r≒4×10
9, and then to a turbulent layer at G
rP
r≒10
10. In the vortex street layer, the geometrical configuration of which is similar to that of Karman vortex street, the pitch of the vortices and the number of the vortices developed per unit time are kept constant respectively. Then it is tried to analyse these experimental data theoretically. Though the theory is very simple, the results are in nearly good agreement with the experimental data.
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Tetsu FUJII
1959 Volume 2 Issue 8 Pages
555-558
Published: 1959
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The free convection heat transfer from a vertical cylinder of about 360 mm in height and about 76 mm in diameter to ethyleneglycol or water has been studied experimentally. The local heat transfer coefficients, which are measured directly, are scarcely affected by the development of the vortex street in the boundary layer, but are discontinuously increased by the transition to a turbulent flow. The results for ethyleneglycol are as follows : G
rP
r < 8.5×10
9 : N
ux=0.49 (G
rxP
r)
1/4 8.5×10
9 < G
rP
r < 8×10
10 : N
n=0.87 (G
rP
r)
1/4 The temperature distributions in the boundary layer are also measured.
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Tetsu FUJII
1959 Volume 2 Issue 8 Pages
559-563
Published: 1959
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In the analysis of the turbulent free convection two different solutions are obtained ; one has a fundamental assumption that the temperature and velocity distributions in the boundary layer respectively take similar figures along the flow, and the other has a fundamental assumption that the laminar sublayer takes a Reynolds number 160. The former corresponds to the transient turbulent boundary layer and the latter to the ordinary turbulent boundary layer. Then referring to the experimental results, the most appropriate dimensionless heat transfer coefficients are represented.
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Seikan ISHIGAI, Kotohiko SEKOGUCHI
1959 Volume 2 Issue 8 Pages
563-568
Published: 1959
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The energy equation for a single-phase flow is usually applied to predict the pressure drop of the flashing flow of steam water mixtures. This energy equation must be solved in such a way that the solution may not only give the relations among the pressure drop, the mass flow rate and other factors, but also be applicable without discrepancy to the critical flow. In this paper, a new correction factor ψ
m for friction loss is introduced to satisfy the above mentioned requirements and is determined by experiment. The factor ψ
m is the ratio of the true coefficient of friction for the flashing flow to the calculated coefficient of friction for a homogeneous flow. An empirical formula for ψ
m is determined from the experiments over a pressure range from about 3.5 to 8 ata, a range of the length of horizontal pipe line from 1 to 10 m, and a range of the internal diameter of pipe 10.0, 6.2 and 4.1 mm. The equation ε for critical flow rates is also developed by using the empirical formula of ψ
m.
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Kusuyata TANAKA
1959 Volume 2 Issue 8 Pages
568-572
Published: 1959
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When radiant energy is emitted in the space which is composed of surfaces 1 to n and gases 1'to l' as shown in Fig. 1, the temperature of each surface has been already obtained, assuming that both distributions of the temperature and the heat flux on it are uniform. In this paper, I will show a method by which, on the same assumption, both distributions of the temperature and/or the heat flux on each surface may be calculated as the second approximation. The distributions may be obtained by considering heat balance, when overall interchange factor between an infinitesimal surface p on a surface m and a surface or gas x, (x, p) are determined. (x, p) may be obtained as follows. [numerical formula] where Δx
m/A
m represents (x, p)^^
-/A
p-(x, m)^^
-/A
m, and 1, 2, ……, i, ……, m, ……, n specify n surfaces, respectively. x represents an arbitrary surface or gas, which composes the space, and p an infinitesimal surface on m. (x, m) and (x, m)^^
- mean overall and one-way interchange factor between a surface m and a surface or gas x, respectively. εis emissivity.
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Fujio NAGAO, Yuzuru SHIMAMOTO, Hidehiko OBAYASHI
1959 Volume 2 Issue 8 Pages
573-578
Published: 1959
Released on J-STAGE: February 15, 2008
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The measurement of the exhaust-gas energy is essential for the design of turbochargers. However, in a pulse system its direct measurement is next to impossible. The present authors have devised a simple method for this purpose. A part of the exhaust gas is by-passed to expand down to the atmospheric pressure through a small measuring nozzle similar to the turbine nozzle. The momentum of by-passed gas is measured as the thrust on a cage, built of piles of aluminum rings and a disc lined with wire gauzes, and the flow rate, by means of an orifice. Thus the mean ejecting velocity of the gas from the turbine nozzle can be calculated. It has been confirmed that the exhaust-gas energy can be determined by the above mentioned method with tolerable accuracy.
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Fujio NAGAO, Yuzuru SHIMAMOTO, Hidehiko OBAYASHI, Takehiko KURATA
1959 Volume 2 Issue 8 Pages
578-583
Published: 1959
Released on J-STAGE: February 15, 2008
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In order to increase the delivery ratio and the scavenge pressure in a crankcase-scavenged two-cycle engine, the crankcase volume must be made as small as possible. However, there exists the constructional restriction. On the other hand, the delivery ratio is considerably affected by pressure fluctuations in the exhaust and inlet systems. The present authors have experimentally investigated the effects of the crankcase volume and of the exhaust and inlet systems on the delivery ratio. It was confirmed that the drop in the delivery ratio caused by the increase in the crankcase volume could be fairly well compensated by tuning the exhaust and induction pipes. Finally they found out the conditions to improve vastly the delivery ratio by the properly tuned exhaust and induction pipes.
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Yasutoshi NAKAYAMA, Hideo ENDO
1959 Volume 2 Issue 8 Pages
584-593
Published: 1959
Released on J-STAGE: February 15, 2008
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To make fully sure about the effect of honing, the authors tested with a diesel engine which had both fine-bored and honed cylinders. Careful investigations were made on 1) cylinder : amount of wear (as measured by the air-micrometer), roughness 2) piston : amount of wear of piston and ring grooves, distribution of temperature 3) piston ring : amount of wear, tension, distribution of pressure, movement in cylinder, roughness and 4) compression pressure. After one year and a half measurement, the following conclusions have been reached : 1) Wear of a honed cylinder is smaller than that of a fine-bored cylinder at initial stage, but with regard to the total wear, there is no difference between them. 2) In other respects, there is no difference between them either. 3) So honed ordinary cast iron cylinders shorten the fitting time, but fine-bored cylinders serve the purpose in other respects.
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Akira UJIIE
1959 Volume 2 Issue 8 Pages
594-601
Published: 1959
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Various welding problems in the fabrication of high pressure boiler are divided into five groups and discussed as follows : Materials ; Author discusses how to weld heavy wall low alloy steel main steam pipes in the field and also introduces the difficulties encountered with the austenitic piping in the operation and the results of laboratory welding tests conducted with the austenitic piping from the literatures. Welding Machine ; Author discusses various types of welding machines which are applicable for the drums, pipes and tubes. Inspection of welded joints ; Author shows various methods of non-destructive inspection and their typical applications. Heat treatment ; Author made his own experiment to determine the holding time for post heating and the method to interrupt the heat cycle of heavy wall pipe welding. Root pass welding ; Author shows how to use EB insert ring, kellog's method and GE method for the root pass welding without backing ring.
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Rikiya TAKEDA
1959 Volume 2 Issue 8 Pages
602-608
Published: 1959
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In the preceding papers, the author described the characteristic of the current meter with the axis placed parallel to the flow. In this report, he has studied the characteristic curve of the current meter in the tilted flow and classified current meters into four categories in accordance with the type of aerofoils of their runner and with the error character on their indicated velocity under the influence of the tilted flow. By combining characteristic curves of more than two out of the simplified runners, the author has succeeded in trial production of a combined aerofoil current meter, which satisfies the cosine law under the influence of the tilted flow.
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Marusuke GOMI
1959 Volume 2 Issue 8 Pages
608-615
Published: 1959
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This report suggests a simple formula for calculating the mean outlet flow angle deviation caused by the secondary flow in turbine cascades of semi-infinite span, assuming the secondary vortices concentrated on their centroid, then deriving secondary velocities along the trailing edges and computing the actual vane circulation using Smith's equation. As a result, the following conclusions are obtained ; (1) Deviation of outlet flow angle increases with the increase in the inlet flow angle. (2) Deviation of outlet flow angle increases with the increase in the spacing of cascade, especially in impulse cascade of large camber angle. (3) Calculated results were compared with some experiments and fairly good coincidence was obtained except the effect of passage vortex of impulse cascade being pushed towards the mid-span.
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Goro KAMIMOTO, Hisashi ANDO, Teruaki AKAMATSU
1959 Volume 2 Issue 8 Pages
616-623
Published: 1959
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The air test of a model of the propeller turbine was performed to reconsider the methods of designing Kaplan turbines by the usual two-dimensional treatments. The performances of it, the flow conditions at the inlet and outlet of the runner and the pressure distributions on the running blades were measured to compare with the ones of two-dimensional cascades.
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Goro KAMIMOTO, Yoshihiro MATSUOKA, Hideo SHIRAI
1959 Volume 2 Issue 8 Pages
624-629
Published: 1959
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This paper deals with the effects of fluid viscosity on the performance and pressure distribution along the vane surfaces of the impeller of centrifugal type hydraulic machinery. The viscosity of water was changed by adding glycerin. An impeller with 6 vanes, vane angle 30° and inner-outer radii ratio 0.6, was rotated in the solution of glycerin mentioned above, and then the head, flow quantity and the pressure distribution along the surface of the vane were measured.
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Goro KAMIMOTO, Yoshihiro MATSUOKA
1959 Volume 2 Issue 8 Pages
630-637
Published: 1959
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This paper deals with the theory of the impeller of centrifugal type hydraulic machinery with vanes of arbitrary shape. The theory contains a method of conformal mapping based on a mapping function, which maps conformally an impeller with logarithmic spiral vanes. into a unit circle. The calculated results were compared with the experimental ones of impellers. with three types of vanes.
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Sigezo IWANAMI, Hiroshi KATO, Norisige TIKAMORI
1959 Volume 2 Issue 8 Pages
638-643
Published: 1959
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We have carried out some experiments to find out the behaviour of oil leakage from an O-ring packing used for the gasket and reciprocating parts. The chief points of the results of this investigation are : i) For the gasket : The seals can be made perfectly leakproof for oil pressure up to 280 kg/cm
2 (4000 psi limit of this test pressure). ii) For the reciprocating use : It has been shown theoretically and proved experimentally that the quantity of oil leakage from an O-ring is proportional to the square of the reciprocating velocity of the road, the n-th power of the kinematic viscosity of the oil. In this case we have n≒1 for the values of ν measured at the working pressure from analytical treatment but n=1.5 for ν measured at atmospheric pressure from experimental results.
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Iwao OKI, Kosaku KAWAKAMI
1959 Volume 2 Issue 8 Pages
644-650
Published: 1959
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In an angle-valve type valve box specially prepared a series of experiments were carried out on disc valves with flat-or conical-seat under a head of about two meters. Thus the relations between valve lift, discharge and lifting force were studied, whereby many factors in the characteristics of disc valves under these conditions were made clear.
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Iwao OKI
1959 Volume 2 Issue 8 Pages
651-657
Published: 1959
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We have made an overall study of our experimental researches on disc valves which were reported one after another since the year 1921. Many factors have been thereby brought into light as to the characteristics of disc valves with flat-or conial-seat, through which water was discharged in valve chambers of vertical cylinder type or angle-valve type, or discharged freely into the air.
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Yukio TOMITA
1959 Volume 2 Issue 8 Pages
658-662
Published: 1959
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At low velocities the flow of wood pulp slurries in a pipe line is similar to the flow of Bingham fluid, and a thin water film exists between the wall and the main body of the pulp during pulp flow at usual velocities excepting low velocities. The author shows that the coefficient of pipe friction loss f is a function of the single dimensionless number [numerical formula] through all velocities (ρ
p : pulp density, μ
a : average velocity, τ
y : yield stress, α : relative plug radius). Moreover, the singularity of the pressure drop of the flow of sulphite pulp (the pressure drop shows a slight decrease with an increasing velocity and at higher velocities the pressure drop again increases with an increasing velocity) is also explained.
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Yukio TOMITA
1959 Volume 2 Issue 8 Pages
663-669
Published: 1959
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When the high speed aerodynamic characteristics of airfoils were investigated by the experimental method using a shallow water flow with free surface, the author showed that four dimensionless numbers must be equal for the flows around two airfoils in order that the variations of water depth around two geometrically similar airfoils might become similar to each other. However, as it is difficult to make these four dimensionless numbers equal for the two systems at the same time, the quantitative experimental results necessitate a certain defined magnitude of airfoil and water depth. On the other hand, the experimental results of the defined magnitude of an airfoil by the water flow of defined depth with free surface are different from the wind tunnel experimental results of the airfoil, because both Reynolds numbers differ from each other considerably. Therefore, comparing both experimental results, the experimental formulae of correction were found. Moreover, the photographs of flow pattern around airfoils were taken, to make the conditions of flow clear to a certain extent.
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