Rotational bending fatigue tests for carbon steel, KSF60 and low alloy steels, KSFA80, KSFA110 were car-ried out to clarify the property of fatigue strength of high tensile forged steels. Fatigue fractures of low alloy steels occurred even though the repeated stress exceeded 10⁸ cycles, which started at interior non-metallic inclusions.
Fatigue strength of the forged material shows anisotropy depending on the relative direction of specimen to forged grain flow, and it is shown that this anisotropy of fatigue strength is due to the projective shape/size of non-metallic inclusions at crack origin to a plain perpendicular to the maximum stress direction. The effect of non-metallic inclusion to fatigue strength was estimated using √area parameter model.

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A novel zero current switching high frequency inverter as a power supply for the high-intensity ultrasonic homogenizer was developed to realize the high cost performance and stable operation in wide range of load. In this paper the procedure of the circuit design was described on the basis of numerical analysis with respect to the distortion factor of output voltage, power factor and switching stresses. Furthermore, the emulsified fuel oil with water by using high-intensity ultrasonic homogenizer was generated and estimated.

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Abstract It has been known that fossil fuels, especially petroleum, are giving out in recent years on a worldwide scale. Since the estimated amount of coal deposits is abundant, the adaptability of coal-liquefied oils (Light Naphtha & Fraction Gas Oil) for diesel engines has been studied. Coal was pyrolyzed and then coal-liquefied oils were extracted. The results of fundamental experiments on ignition time, ignition temperature, kinematic viscosity and calorific value of coal-liquefied fuels and its blended fuels with gas oil, and the engine performance on these fuels are described in this paper.

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A new concept of a support system for marine engine system operation using oral communication and simulator techniques based on the chief engineer's knowledge and his experiments has been studied. In the near future, a deck officer who is inexperience it will operate the marine engine system. The emergency and ordinary start-stop conditions of the engine system easily make the crew operate incorrectly which leads the engine system failure status because of complicated procedures for an inexperienced one. Commonly intellectual automatic control system is introduced to cope with this situation, though it can only operate the engine system for a load change and indicate the troubling parts of the engine system. We have proposed and been developing the Chief engineer system (CE-SYS) which instructs the crew about the preferable operation in each step of the engine conditions. These instructions are made by the CE-SYS, which acts as the chief engineer's behavior using the engine system status simulator and the database of the chief engineer's knowledge.
The CE-SYS has some features and merits as follows;
(1) The oral communication and the graphics display techniques are adopted to communicate between the crew and the CE-SYS.
(2) The crew receives proper instructions of the engine system operation from the CE-SYS.
(3) The CE-SYS understands by setting a condition on the engine system status simulator same as the engine system current condition.
(4) The crew studies the proper procedures from orders made by the CE-SYS.
One of the purposes of the CE-SYS is to train the crew up to expert engineers.
It is quite different from the purpose of the ordinary automatic system, which is to operate or to control directory the engine system without the crews operation.

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