It has been well known that SUS304 stainless steel may be sometime caused stress corrosion cracking (SCC) due to chlorine ions with two kinds of process. One is sensitization SCC caused by ingress of chlorine ions into sensitized grain boundaries in which chromium carbides or chromium deficient area may be formed by unsuitable welding condition such as improper welding heat input management or incorrect welding speed, etc., cracks will be initiated and propagated along this sensitized grain boundaries. The other is SCC caused on SUS304 stainless pipes covered by insulation material. This paper focuses on the later cases of SCC which was caused on cargo pipelines made of SUS304 stainless steel covered by insulation material in a chemical carrier.
At the Eighth ME Salon on 29 October 2021, the author delivered a lectured entitled "Looking Back on My Career as Marine Engineer for Nearly 39 Years", and shared some impressive experiences about marine engineering tasks on a mother ship, freezing carriers and training ships. This paper extracts some episodes from this lecture and presents operational problems the author encountered with a double-acting diesel engine and single-acting uniflow diesel engines. It also covers operational failures the author experienced on a new freezing carrier and freezing carriers powered by low quality marine fuel oil. The purpose of this paper is to transfer knowledge and technology to younger generations, and this is in line with the main goal of the ME Salon.
A deceleration method was employed to measure the friction loss in a 2-Stroke spark-ignition engine for a racing boat. In order to reveal the effect of the friction loss on the acceleration operating characteristics, a transient operation test system was developed in a usual performance test setup. By adjusting the input current into the field coil of the eddy-current dynamometer, the acceleration operation behaviors were mostly simulated except for the initial rapid acceleration. Two kinds of pistons having different skirt dimensions were applied to the deceleration test to obtain the friction loss. These pistons were also applied to the acceleration operation test, and it is shown that the engine friction effect could appear in the acceleration operation characteristics according to that predicted from the friction measurement results on the whole.
The present paper refers to our study on reducing friction on reciprocating sliding surfaces by surface texturing. The purpose of this study is to develop optimal design guidelines for surface texturing by clarifying its effect on the lubrication characteristics of reciprocating sliding surfaces under various operating conditions. Numerical analysis has been performed by solving the Reynolds equation using the finite element method to evaluate the effect of surface texturing．The major results are that; 1) The reciprocating friction characteristics of a barrel face slider with groove-shaped surface texturing can be organized by the bearing modulus consisting of the viscosity coefficient of the lubricant, average sliding speed, and surface pressure.; 2) Friction loss is reduced by applying groove-shaped surface texturing with appropriate depth and arrangement according to the value of bearing modulus, as compared with the case of no texturing.
One of the technologies required for fully autonomous ship operations is an unmanned/automated watch-keeping system using camera images. Methods to detect objects, such as ships, from images have long been studied. However, it has been difficult to recognize the target when it is surrounded by complex background or it appears tiny due to long distance. In addition, the environment surrounding the ship, such as the land, harbors and quays, also needs to be recognized appropriately. This paper proposes a method to recognize the peripheral area with camera images utilizing deep learning. It then describes the results of three experiments we conducted by dividing the surrounding area into the sea, land, sky and ship segments. Using these segmentation results, we partially enlarged the images to reexamine the existence of ships in the background. The experimental results successfully identified more ships that appeared a long distance away after enlarging the images of the border areas between sea and sky/land.