When Stokes waves on the ocean approach to sea shore, wave hights and drift current gradually decrease. So that usual waves with moderate period become smooth somewhat likely to long or solitary waves. However, extremely long waves such as caused by earthquake grow higher and higher at the beach. These are named as Cnoidal waves. In estuary or river-mouth there often occur high waves, which are always on drift or tide current with contrary direction to progressive ocean waves. This paper is some considerations to these phenomena. The maximum wave steepness can reach, which might be seen rarely, 0.407, but the ratio of water depth to wave length is about 1/10 the above value decrease to 1/2.

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The Purpose of this research was to analyze how the objectives which the producer had were reflected in the content, construction and representation techniques of the program he made and to evaluate to what extent students could understand it. In order to clarify the objectives of the program adopted in this research a brief interview was held with the producer beforehand. The measurement tools were a pre-test, a post-test (both of them developed by our research members) and a response analyzer. The TV program used in this research was "Living things in the tidepool" which was broadcast on June 5th in 1984. (NHK) The main results were as follows. (1) According to the producer, the most important objective of the program was "understanding of the program as a whole" or "understanding of how living things in the tidepool adapt to their environment. "Analyzing the test results, it was found to be almost achieved. (2) The test scores in relation to factual knowledge were low. But the memorization of facts was not an objective of the program. So this result is not thought to be the evidence of the program's fault. (3) There were two special representation techniques used in the program. They were effective in terms of arousing affective response of the students. (4) There was no difference in the degree of understanding of the program between the two grades (6th-9th). Furthermore, there was little difference between the teachers and the students. This is a desired outcome of the program of this kind. (5) The results of the response analyzer showed that there was a main difference between the cognitive and affective response pattern of the students and the importance response pattern of the teachers. By this, it could be said that the teachers and the students, both receivers of the same program, tend to be differently affected by the program depending on whether the purpose to watch it is the preparation for instruction or the learning of new information. The conclusion is that the program evaluated in this research was effective in terms of the attainment of the producer's objectives.

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The possibility of using granulated blast furnace slag was investigated in the present study, because in the near future it may become more difficult to obtain marine sand on a massive scale. Granulated blast furnace slag is a by-product from the manufacturing of iron. It can act as an alternative material to marine sand for constructing artificial tidal flats and shallows. This studies were conducted at a Tidal Flat Mesocosm System (5m x 8m) which can reproduce physical conditions of a tidal flat such as tidal level, tidal current, wave and wind. The effect of five kinds of granulated blast furnace slag, including mixture by natural sand was assessed on the basis of the structure of benthic community, and larval settlement, post-settlement survival of the Japanese Littleneck Clam, Ruditapes philippinarum. The effects were compared to five different kinds of natural sand. There was no significant difference in the benthic community such as bacteria, meiobenthos and macrobenthos between the blast furnace slag group and the natural sand group. On the other hand, there was no significant difference in the larval settlement and post-settlement survival of Ruditapes philippinarum between the granulated blast furnace slag group and the natural sand group. From the results of these two experiments, the possibility to used the granulated blast furnace slag as an alternative material to marine sand was suggested.

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