Online ISSN : 1884-4758
Print ISSN : 0388-3051
ISSN-L : 0388-3051
Volume 25 , Issue 12
Showing 1-5 articles out of 5 articles from the selected issue
  • [in Japanese]
    1990 Volume 25 Issue 12 Pages 759-764
    Published: December 01, 1990
    Released: May 31, 2010
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  • Goji Ikegami, Zenichiro Yoshihara, Yasuhiko Senba, Toshisuke Kubo
    1990 Volume 25 Issue 12 Pages 765-771
    Published: December 01, 1990
    Released: May 31, 2010
    Breakup of water droplets is influenced considerably by the velocity distribution of gas flow. The experiment was conducted using high speed cameras and simple shaped nozzle plate edges, from where water droplets are separated, suddenly accelerated and broken up by diffusing high speed air flow. It is presented in this paper that a) the effects of velocity of air flow on water droplets' diameter, and on breakup distance from the plate edge, b) the acceleration states of water droplets, and c) Weber number at the breakup points. Droplets have two types of breakup process, and Weber number takes rather wide range and lager values than that in the parallel and uniform flow.
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  • Tadao Nakamura, Yoshihiko Irie, Iwao Honda
    1990 Volume 25 Issue 12 Pages 772-776
    Published: December 01, 1990
    Released: May 31, 2010
    To attain the quietness of vehicles such as automobiles, ships and airplanes, which are mostly composed of plate elements, the reduction of structure-borne noise is important, and for which the damping treatment by using viscoelastic materials is effective.
    In adoption of this treatment, difficult problems are the systematic design of damped structures and the prediction of damping effects, taking the damping material properties into acount.
    To develop a systematic design tool for damping treatment, 1st report has already revealed the prediction procedure of the damping effects of structures attached viscoelastic materials of which dynamic properties are known, and this paper presents a estimation method of damping properties of viscoelastic materials from vibratory characteristics of a sandwiched beam.
    The discussions of this paper are as follows.
    1) To obtain the dynamic properties of viscoelastic materials as shea modulus and loss factor, the symmetric sandwiched beam method is applied, and their properties are estimated from measured data of modal frequency and loss factor of sandwiched beam.
    2) To ensure the estimated result by this method, the effective range of the modal loss factor and the natural frequency ratio of the sandwiched beam in reference to the undamped beam is shown.
    Dynamic properties of a damping material estimated by using this technique shows a good result.
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  • Hisaharu Sakai, Sadami Yada, Makio Sakamoto, Hayao Akizawa
    1990 Volume 25 Issue 12 Pages 777-781
    Published: December 01, 1990
    Released: May 31, 2010
    The estimation of necessary power which determine the generator's capacity is based on the capacity of the equipped electric apparatuses to be equipped during the planning stage. The increase of electric power consumption caused by increase of electric apparatuses and the increase in specific fuel consumption caused by deterioration in performance of the engines are observed as years go by.
    Investigations were conducted to analyze the age deterioration of electric power equipments by experiment based on the vessel's log books.
    The following conclusions were obtained.
    1) Increase of electric power consumption is 2.2KW per year, with almost no recognizable difference in electric power between normal runnig service and in-port service.
    2) The deterioration in performance of engines by exhaust gas temperature, expressed in load [KW], is 0.8KW per year.
    3) The Age Deterioration of Electric Power Equipments estimated in electric power [KW], is 3.0KW per year. This value is equivalent to 1% of the main generator's capacity.
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  • Hachiro Kido
    1990 Volume 25 Issue 12 Pages 782-797
    Published: December 01, 1990
    Released: May 31, 2010
    A reliable survey of Diesel Ship has been carried out with many reserch departments even until now. Accordingly, it is understand that situation of an about outline regarding the failure in a ship's equipment.
    However, the one that was investigated and remain about the situation of the alarm that occurs with the 1st stage of failure is nonexistent.
    Also, the example that operation situation of a ship was analyzed, regarding the influence that gives to an Alarm Rate and a Failure Rate is scarce.
    First of all, a M0 operation and an Alarm Rate of a ship tried to be checked mainly here.
    Also a survey was added regarding a Failure Rate of devices needed for an analysis.
    Next, a survey was carried out about an Alarm Rate and the place ingredients man * hour every constitution devices of Diesel plant.
    Also, it investigated whether or not an Alarm Rate receives an influence by a kind of ship and ship's. ages.
    The following case understood as a result of a survey.
    An Alarm Rate decreases by the thing that devices main body raise reliability more to fuel oil.
    Failure that depends indistinctly and originate to the alarm monitoring system is many.
    Beside such way that pick up a cause of failure is required the reliability of instrumentation devices oneself need to be raised.
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