This paper describes the experimental study on burning time of the suspended single droplet of fuel oils in the high temperature air under atmospheric pressure. The fuel oils used in the experiment were twelve marine fuel oils.
The results show that the burning time of single droplet is determined by the mass of droplet at ignition and the evaporation rate during burning, and it decreased under both lower and higher ambient temperature. Therefore, the burning time took the maximum value with the change of the ambient temperature. The mechanism of the burning process of these droplets was investigated.
The life time of droplet is influenced by the ignition delay rather than the burning time, and it decreased with the increase of ambient temperature.

View full abstract

It is well known any preventive maintenance method is not always useful in cases where system failures roughly follow the exponential distribution. In order to overcome this weakness, the monitoring maintenance was introduced recently and attracted the attention of the engineers as one of the most effective methods to prevent a system from defects and failures. The present authors, Horigome and I, lately introduced the success ratio of fault diagnosis they investigated the characteristics of the preventive maintenance from the viewpoints of the reliability improvement ratio, the maintenance cost and the maintenance numbers. In this case, it is assumed that the system failure occurs through some malfunction, and follows to an exponential distribution. Then the newly obtained results are discussed. Finally it is shown that they are very useful for analysis or investigation on the maintenance in the field.

View full abstract

Wear resisting steel (WRS), improved scuffing characteristics was newly developed in order to apply to the frictional parts for machinary. The two rollers tests were carried out using the newly developed WRS, steels with Ni-P electroless plating, and with electrolyzed and sulfurizing treatment. Then the scuffing characteristics of these materials were discussed.
The anti-scuffing characteristics of WRS were very good and the frictional coefficient was as small as about (1/3) of SUJ2, a reference material. From the test results using WRS specimen of two kinds of hardness, the anti-scuffing characteristics of specimen of which the hardness was low was higher. The anti-scuffing characteristics of steel with Ni-P electroless plating were good. The part of Ni-P electroless plating layer remained during the test period but the other part of plating layer disappeared. On the other hand, the electrolyzed and sulfurizing layer which is effective for running-in, disappeared in a short time, and became that of base material.
As the result of observation of surface and cross section of specimen, the white layer on the scuffing surface was found from 30 to 50μm thickness. It seemed that the layer is a martensite including supersaturatedly solidified carbon which is a part of cementite at the sub-surface dissolved by thermal and mechanical energies.

View full abstract

A research in which laser light scattering and attenuation techniques are applied simultaneously in a complimentary fashion is fully investigated to allow the determination of size and number density of particulate matter concentration in exhaust gas from steady flame at real time. The particulate matters, however, seem to be dispersed or cluster-like, spherical or maybe of any sizes, including Rayleigh-size, for which it is particularly difficult to infer simultaneously particle size and concentration. This study is based on the theories of Rayleigh-Debye about light scattering and the form of the particulate matter in exhaust gas is cluster-cluster-aggregation, called Cluster-Rayleigh-Debye model. The main point of this technique is combined of using laser light scattering for the case of scattering angles of 40deg. and 140deg. and attenuation technique with two laser light sources individually. 50 (mW) and 15 (mW) Helium-Neon laser light sources emitting monochromatic radiation at a wave-length of 632.8 (nm) are used as incident light sources. In the present study, the detailed profiles of size and number density of particulate matter concentrations in exhaust gas from steady flame are obtained. The dependent on intensity level and refractive index variations can be neglected. The application and results of this method are fully investigated, compared to those of system using filter and discussed.
From results of the experiments, it can be concluded that the implementation of the Cluster-Rayleigh-Debye model system has been realized successfully to provide particulate matter concentration in exhaust gas from any steady flame at real time and those are fundamental for next stage experiments on unsteady flame and diesel engines. There is no significant difference between the result of this optical method and filter system.

View full abstract

In the conventional system of lubrication, lubricating oil is renewed with fresh oil after it is used for some period. Accordingly, waste oil is generated in the conventional system. The authors have developed a new system that makes it possible to use lubricating oil semi-permanently without oil renewal. In the new system, therefore, no waste oil is generated and it is enough to supply only a small amount of fresh oil sometimes to compensate for the lost oil. This system has been working well in about one thousand units of marine and cogeneration diesel engines in practice. The new system always keeps lubricating oil clean as the kidney of animals always keeps their blood clean. This is why lubricating oil can be used semi-permanently and the new system is called kidney system. This technology has been developed based on the assumption that lubricating oil is hardly oxidized contrary to the general knowledge all over the world. This report verifies the above mentioned assumption based on our analysis of used oil in engines in practical use and some data in various fields.

View full abstract

In Japan, packages account for about 60% of total general waste by volume. You see many kinds of containers in this market, such as PET bottles, steel cans, aluminum cans, glass (returnable and one-way) and paper containers.
To reveal which packages are more environmentally friendly, we studied the LCA on the beverage packages using published data. This was done under the leadership of Dr. Yasui University of TOKYO. We determined the recycle and the waste scenario of each packages with the present data. As a result, returnable glass bottles with five and twenty trips and paper cartons showed the lowest environment loads among the packages. Other disposable containers showed similar results and higher environmental loads than returnable glass containers and paper cartons.
This project was only the start line of the comparison among the packages. We expect further data will be available on each container and that results of analysis will be much more practical.

View full abstract