No abstract

In this paper, the history and latest trends in the converter-based steelmaking process in Japan were summarised. After World War II, Japanese steel companies introduced the LD converter, and various original technologies have been developed to increase productivity, reduce the production cost, and improve the quality of steel. About 20 years after the introduction, the necessity of the additional stirring was recognised and various types of top-and-bottomblowing converters were developed. By using this process, hot-metal dephosphorisation and smelting reduction were developed. In addition, fundamental research related to the converter technology is shown. Japanese steelmaking technology has been developed by the collaboration of university and industry. In industry, each company has an R&D centre where the applied and practical research is conducted. The research in academia is concentrated on the fundamentals. Recently, ISIJ organised the research projects on 'multiphase slag refining' and 'enhancement of lime dissolution'.

No swirl motion occurs when the aspect ratio falls between around 1.0 and 2.0 ( Fig. l(b)

The effects of several kinds of permeable spur dike on 3-D flow structures and river bed evolution were investigated in curved open channels experimentally and numerically. In this study, three-dimensional mean flow structures were measured in a curved open channel with spur dikes arranged along the outer bank. Experiments were conducted in movable beds and the effects of spur dikes on the local scour were examined. The secondary flow cell was generated in the same manner as the uniform rod roughness cases. Outer-bank arrangements of permeable spur dikes can reduce the outer-bank scour, but additional scour is generated in different regions. A traditional hydraulic structure, "Seigyu" has the similar effects on flow structures as the pile dikes. A 2-D numerical simulation model can be applied to these spur dike cases with the same assumption for the secondary flow dispersion terms.