In general, the strength of weld joint depends on the thermal cycle of bond. Consequently, it is very important to evaluate the cooling process of bond accurately. In the paper, the cooling process is analysed by means of 3-dimensional F.D.M., where the calculation is executed with a mini-computer (main memory; 128KB) . The simultaneous equations are sloved by Gauss-Seidel method with δ²-extrapolation technique, so the maximum node number of F.D.M. model becomes over 10000. The governing equation here is a quasi-stationary one because heat input by arc is treated as moving heat source. The analyses are done for various welding speeds and plate thicknesses and their effects are discussed. The accuracy of the analytical results is ascertained by the experiment of CO₂ arc welding.

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It is very noticed thing that we have many indistinct problems, at present, on a package boiler having duble cylindrical heating areas made of straight pipes, called“Multi-Tube Type Once Through Boiler of Small Capacity”in Japan.
In this papaer, experimental and analytical results on behabior of the separated water in the header of the boiler are described.
And it is a final conculusion that the boiler is not classified into the reasonable once through boiler of small capacity but the general water tube boiler from the following results.
Results of observing the header with two sight glasses are as follows ;
(1) Large quantity of separated water flow into the outer heating pipes from the bottom of header of the boiler, operating on the usual water level condition.
(2) There exists no over flow water from the great part of outer pipes except for inner pipes, ejecting boiled water and steam continually.
Measuring results are as follows;
(1) Quantity of separated water in the separator properly attached to the out side of the boiler is extremely small, so there seam no especial needs for epuipping the boiler with the separator.
(2) The water temperatures in the outer pipes near the feeder at the middle of convection heating area are higher than those at the corresponding points of the inner pipes.
(3) A lot of thermal energy flow into the feeder, operating at a little higher water level than rated value but within the usual level range.
Results by analytical calculation are as follows;
(1) Average circulation ratio R, which is caused by the falling water in the outrer pipes, at the water level below 5/8 of the pipe length, is very small.
(2) At above 7/8, values of Rincrease rapidly.
(3) Average mass flow ratio of the falling water to the ejecting water in the header indicates the same tendency as that of R.
(4) Average temperature of water in the feeder shows the same rising tendency toward the value at saturation condition as the water level aproaches to 7/8.

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After the oil crisis, the world-wide demand for saving the oil resources has been strong and consequently the need of saving energy in ships has been increasingly large.
In this paper, the fuel economy characteristics of marine diesel engine oils have been investigated by using dynamo-generator diesel engines on board.
In order to study the effect of oil viscosity and friction modifier additives on the fuel economy characteristics of oils, several engine oils different in viscosity and containing fiction modifiers were investigated in comparision with the reference oil having TBN of 11 mg KOH/g and viscosity of 11.68 cst at 100°C.
According to the results, the lower viscosity oil gave better fuel economy characteristics than the higher one, but the use of friction modifiers caused no improvement of the fuel economy characteristics of the lubricants.

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Development of ship's salty and her economical operation are increasingly required in marine transportation field, and in relation to these, higher automation onboard and labour saving system are also required accordingly. However, to proceed more advanced system on above concerns, it is assumed that shore support system would become indispensable.
In such stage, various data communication between ship and shore office would be more and more important. Assuming such status in near future, The AUTOMATION SYSTEM COMMITTEE in MESJ has made some studies on contents and/or forms of mutual data communication based on current INMARSAT.
While, The committee has also studied of participation of personal computer (of which installed comes up popular onboard) in above data communication system.
Thus, studied matters and/or concerns made by aforementioned committee are reported here after.

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It is a recent widerspread tendcy that marine diesel engines are operating with the heavy fuel of low quality, thereby causing trouble of engine plants to rise, and also works on board and repair expenses to increase.
It is expected that the quality of marine fuel will deteriorate steadily for the future.
In order to meet these trends, improvements of heavy fuel treatment have been taken up as the main study themes in shipping companies.
Under circumastances, authors have continued on the reseach and development of heavy fuel treatment system which may cope with the fuel of low quality.
Our reseach has succeeded in bringing forth the new type heavy fuel oil pretreatment system. the “HOPE SYSTEM”.
This paper describes the influenses upon diesel engine plants by the heavy fuel of low quality and the detail relation to research and development of the HOPE SYSTEM.

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