Recently, finite-difference schemes for solving the incompressible Navier-Stokes equations involving various kinds of boundary conditions have focused on improving their accuracy, stability and efficiency. A computer program for solving two-dimensional, time-dependent, incompressible viscous flows using the simplified staggered grid in generalized coordinates named SGGQ2D has been developed by using a new formulation better than the former one called GGQ2D with the regular grid. The 2D momentum equations of Navier-Stokes equations for the J^<-1>u artd J^<-1>v velocity components and the Poisson equation for the pressure field are solved by applying a semi-implicit type time-marching scheme. The spurious errors and the numerical instabilities can be suppressed by employing this simplified staggered grid system and the QUICK upwind control volume scheme in generalized coordinates. Some numerical results of a 2D free surface flow that has a obstacle in the upper region of a channel are shown to demonstrate the reliability and robustness of the present scheme. We also suggest the same computation in the regular grid system (see a GGQ2D code), which has more computational time and less conservation of fluid volume, because it causes spurious oscillation of pressure values when it is applied to complex flow fields.

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A new research project focused on environmental problems of Ise bay was initiated at Yokkaichi University. The project consists of the development of two and three dimensional computer programs and investigations of flow fields of the bay. In this paper, numerical methods adopted in the two dimensional program are described in detail. A new numerical scheme based on F.D.M. on general curvilinear coordinate system is proposed. It is shown that the scheme with a "quasi" regular type grid system has many advantages compared with conventional methods. Simulations of flow fields of the Ise bay subject to M2 tidal oscillation were carried out as the first trial of the computer program. Several types of data such as amplification factors of wave height flow fields of residual currents, and exchange rates of sea water at the inlet of the Ise bay were computed by post-processing the simulation results. To evaluate the accuracy of the computer code, comparisons with observed data were made and fairly good agreements were found between them.

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Food poisonings occurring in our country most often involve vibrio parahaemolyticus, followed by Salmonella, Escherichia coli, etc.. In 1982 and between 1992 and 1993,particularly, Salmonella food poisonings were of multi-occurrence, and in 1996,O-157-induced large scale food poisonings occurred, attracting not a little social attention. Although quasi-standard examining approaches have been established for vibrio parahaemolyticus, Salmonella, O-157,etc., some examinational improvements still remain to be made depending on to the approach. One of these possible examinational improvements involves vibrio K antigen type determination. Although the 37℃-culture method is now generally available, a combined use of 42℃-culture and HCl methods, if necessary, was confirmed to be able to give good results.

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It has been considerecl possible to store the spent nuclear fuel discharged from a light water reactor (LWR) for 1000 years taking the decay of radioactive atoms into account. However, the highly radioactive fuel should be stored for a much longer time, because considerable amounts of very toxic and long-lived alpha emitters will still be present after 1000 years. The radioactive species are classified into three categories : fission products, transuranium elements and neutron induced species. Using the published results on disintrgration rates of the radioactive products, problems associated with the following three options of radioactive waste "disposal" will be discussed. They are (1) Reprocessing of the fuel followed by the burning of Pu in fast reactors, (2) Reprocessing and burning of long-lived redionuclides including transuranium elements by high-intersity neutron induced resections and (3) Storage of the fuel without further processing. The third option (the storage without processing) is, in my opinion, most practical procedure to be adopted in this country.

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A collaborative project entitled 'Reclamation of Tianjin alkali soil by desulfurization by-product, Gypsum' was established in 1996 between Yokkaichi University and Tianjin Academy, Tianjin City, China, through International Center for Environmental Technology Transfer (ICETT). This paper describes the work planned in this project, the nature of general and Tianjin alkali soils, and the scope for amelioration of Tianjin alkali soil. Tianjin alkali soil seems to be distributed in the area of saline soil, and it would be difficult to demarcate between alkali soil and saline soil in Tianjin. However, chemical analysis of the soils from two locations for our field experiments in Tianjin shows that these soils are alkaline soil although the exchangeable sodium percentage (ESP) is lower than that of the alkali soil classified by the Department of Agriculture of USA. The results of two field experiments with Gypsum in other places in China conducted by other scientists support that crop productivity in Tianjin can also be increased by the desulfurization by-product, Gypsum, through reclamation of Tianjin alkaline soil. It is likely that the amount of Gypsum required for the reclamation of Tianjin alkali soil will be much lower than that used for other alkali soils in China.

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There are two parts in this article. In the first part (from section 2 to section 5), I describe the whole structure of the chapter II "Ritsugen" of Takebe Katahiro's treatise Tetsujutsu Sankei and consider the process of an establishment of unknowns and equations in pre-modern Japanese mathematics through an analysis of the chapter. The second part (section 6) consists of the chapter's reprinting with translation and full annotation.

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The TIANYUAN-SHU "celestial element method" is the native algebra of China, the solution of higher degree equations with one unknown. In this method, the unknown is represented using "YUAN" (the element), the known term is represented using "TAI" (the taichi). This method was introduced into Japan through the work "SUAN-XUE QI-MENG" (Introduction to Mathematical Studies), written by Zhu Shi-jie in 1299. "SUAN-XUE QI-MENG" was first republished in Japan in 1658,but research into The TIANYUAN-SHU began before this time. It is thought that Masakazu Hashimoto was the first mathematician studying this method in Japan. After the 1660s, descriptions concerning the TIANYUAN-SHU started to appear in a few books written by Japanese mathematicians. Entering the 1680s, argument concerning the TIANYUAN-SHU became vigorous in Japan. An argument between Yoshinori Isomura and Kiyoyuki Shibata attracted widespread attention. Isomura tried to understand the TIANYUAN-SHU by drawing on his knowledge of Buddhism. He argued that the TIANYUAN-SHU depends on another's power, while the mathematical methods before the TIANYUAN-SHU depend on one's own power, and that the latter is preferable to the former. He thought that solving equations with the TIANYUAN-SHU corresponds to praying to Amida Buddha. Shibata argued that there was something wrong with Isomura's thinking. A person with knowledge of Buddhism is not the same as one who knows how to employ the TIANYUAN (the heaven element), and the TIANYUAN-SHU includes mathematical methods from before the system itself was developed. Isomura's thinking creates complications for beginners studying the TIANYUAN-SHU. It was Masayuki Sato who first correctly used the TIANYUAN-SHU in "Sanpo kongen ki" in 1666.

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In African literature, especially in Nigerian literature, Social Realism was the dominant trend until the mid 1980s, and social comment was the mainspring of the works of Nigerian novelists such as Ben Okri, Festus Iyayi, T. M. Aluko and Ken Saro-Wiwa who was killed by the military government. During the last few years of the 1980s and the begining of the 1990s, a new trend known as Magical realism, has emerged in Nigerian literature. It is true that the elements of magic and the supernatural have always been present in African literature, but they were never the dominant trend. Focusing on "Worlds That Flourish", written in the late 1980s, I would like to clarify that through Magical Realism, the social reality of Nigeria that has been ruled by the brutal and irrational military government, could be depicted more vividly, and that Magical Realism is, in a sense, a deepening of Social Realism through which social comment can be caused.

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