JOURNAL OF THE MARINE ENGINEERING SOCIETY IN JAPAN
Online ISSN : 1884-4758
Print ISSN : 0388-3051
ISSN-L : 0388-3051
Volume 27 , Issue 5
Showing 1-6 articles out of 6 articles from the selected issue
  • Kojiro Shimamoto, Hiroaki Morita, Yasuo Kannoto, Yoichi Iwamoto, Setsu ...
    1992 Volume 27 Issue 5 Pages 368-374
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    One of the most important theme to develope superconducting thruster engine for ships is to reduce the weight of magnet. So we studied and analizedd the stress working on the magnet in detail and developed the countermeasure for it.
    Instead of the conventional laminated stainless steel collar plate type structure against the magnetic force, the use of rigid and stiffened shell type structure made of alluminnum alloy has led us to find it working more effective against the force less weight in total.
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  • Kojiro Shimamoto, Chiaki Matsuyama, Hiroaki Morita, Yasuo Kannoto, Mas ...
    1992 Volume 27 Issue 5 Pages 375-382
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    For the purpose of preventing the superconductor from quenching, the magnetic coil must be precompressed and be kept in high reigidity.
    On the other hand, the pressure must be controlled abequately to be free from the insulation breake on the conductor caused by over precompression stress.
    We investigated compressive characteristics of the laminated superconductor coil and obtained the optimum value of precomp-ression and the method of assembling the coil. Further we confirmed the steress behavior in the coil during magnet operating conditions.
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  • Yukio Takahashi
    1992 Volume 27 Issue 5 Pages 383-389
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    On a digital force transducer utilizing magnetomechanical effect (Villari effect) of ferrite core, experimental results are presented in this paper. This transducer is a relaxation oscillator which consists of an Esaki Diode and a pressure head.
    The input is a compressive force and it is transduced into an output oscillation frequency.
    The input range is up to 1.2×103N. Nonlinearity and hysteresis error are±1.3% FS, and temperature dependence is less than 0.018%/°C.
    The transducer has a simple digital sensing system and a small temperature dependence, is suitable for a telemeter.
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  • Kikuo Fujita, Shinsuke Akagi
    1992 Volume 27 Issue 5 Pages 390-399
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    A computer system using AI technique is developed for the design of marine power plants and land-use cogeneration plants. In the system, the design procedure of the plants is divided into two steps, namely, (1) selecting the candidates of the machinery and equipment composing a plant, and (2) determining their size and characteristics optimally by considering their operational conditions. In order to support the above design process, a hybrid procedure with AI technique and numerical optimization is adopted. The developed system is applied to the design for both of a marine power plant and a land-use cogeneration plant. Through the system's execution, its validity and effectiveness is ascertained.
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  • Masakazu Ito, Takeshi Katagi, Kenya Sakamoto, Takeshi Hashimoto
    1992 Volume 27 Issue 5 Pages 400-408
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    This research aims at establishing diagnostic monitoring techniques for three-phase induction motor systems using acoustic analysis on order to substitute for engineer's diagnosis.
    This report describs the change of specific frequency components of acoustic sound of operating three-phase induction motors under the condition of unbalanced circuit parameters caused by stator or rotor circuit damages such as disconnection or short circuit. Experiments were made for discussing failure diagnosis by detecting the specific frequency components of the sound of a motor. The following results were obtained by the acoustic analysis of the sound at the surface of the motor.
    1) Under abnormal conditon with unbalanced circuit parameters of the stator, it is possible to diagnose by comparing the sound power spectrum amplitude of the 2f0 frequency component with that of normal conditon where f0: an electric source frequency [Hz] .
    2) Under abnormal conditon with unbalanced circuit parameters of the rotor, it is possible to diagnose by detecting the beat sound of fr, fr±2 sf0 frequency components, where fr: notation frequency of rotor, s: slip.
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  • Masahiro Moriguchi, Yasuhisa Tanaka
    1992 Volume 27 Issue 5 Pages 409-414
    Published: May 01, 1992
    Released: May 31, 2010
    JOURNALS FREE ACCESS
    Oil Purifier has been so far the most important marine auxiliary machine and has played the role of purifying the fuel oil and lubricating oil of main engines and generators.
    By the way, when we consider the condition of oil to be treated by Oil Purifier, we find that the content of demand for recent petroleum products is greatly changing.
    In order to cope with this situation, it is the present codition that we have made best efforts for improvement and betterment of petroleum refinery technique and consequently a deterioration of heavy fuel oil used in vessels has been brought about.
    Giving an example of the main things of the deterioration of heavy fuel oil, the followings are cited;
    1: Increased viscosity (maximum: 700 cSt/50°C)
    2: High density (the density of some heavy fuel oil exeeds 1.0g/l)
    3: High concentration sludge
    4: Mixing of FCC catalyst
    In consideration of these conditions, not to mention betterment of Oil Purifier, the developement of heavy fuel oil treating dystem based on the new idea combining various systems including the Oil Purifier is urgently needed.
    On the one hand, regarding the lubricationg oil, with the change of quality of fuel oil and increased output of main engine, a further superior detergency and oxidation stability are demanded and as a result of this, various additives are developed and used.
    Moreover, in order to improve an economy in connection with shipping service, a shipping service by small number persons as represented by pioneership is now becoming a mainstream.
    Judging from this point of view, a further improved reliability and labor saving of maintenance work are strongly demanded.
    As mentioned in the above, the environment surrounding Oil Purifier is getting more harsh in comparisons with the former times. However, among various countermeasures now being taken to these problems, as the system which we are now developing is considered to display a great power in improving the reliability and the labor saving of the inside work in vessels, we would like to present to you our new system 'The Oil Purifier Sludge Discharge Intaval Automatic Setting System'.
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