A novel lubricant material, calcium N-lauroyl taurate (C11H23CONH(CH2)2SO3·0.5Ca, CaLT), has been synthesized and characterized. The powder of CaLT is a plate-shaped crystal with a lamellar structure. CaLT shows superior lubricity as a result of its unique internal and aggregate structure. When the CaLT powder is applied to an artificial skin, the frictional coefficient is favorably lower than that of other solid lubricants of similar type. The frictional coefficient of CaLT decreases rapidly at initial passage and becomes constant when CaLT is repeatedly rubbed onto an artificial skin. The high lubricity may result from disintegration of the powder aggregates, cleavage of the lamellar layers and deformation of the powder particles. This novel lubricant material, CaLT, will be a powerful ingredient of some cosmetic and/or personal-care products in the near future.

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This paper presents the results of examination on wave transmission over a low-crest artificial double reef which is made of wave dissipating concrete blocks. In the experiment, the ratio of the submerged depth of crown of reef to the incident wave height, R/HI, was set in the range of 1.10 to 4.98. The relative width of the reef against wave length, (B 1+B2)/L varies from 0.76 to 2.16. The relative spacing of the structures against wave length, l/L has a variation form 0.23 to 1.30. In the case of total width of double reef, B'(=B1+l+B2) is equal to width of single reef, B0, KT of double reef is almost equal to KT of single reef. KT decreases following an increase in B/L, and KT becomes the minimum value in the case of l/L=0.23 or 1.10.

This paper presents the result of hydraulic model experiments on the coefficients of wave transmission over a low -crown-height type artificial reef which is made of wave dissipating concrete blocks . The ratio between the depth from water surface to the top of the submerged reef and the incident wave height, R/HI, varies from0.79 to 8.75. The relative width of the reef against wave length, B/L has a variation from 0.51 to 2.53. The wave-breaking limit,R/HI, lies between 0.8 and 1.3 for the above structure. The transmission coefficient, KT, decreases following an increase in B/L.The change of KT is small for a range of B/L larger than 1.6. With regard to the relationship between the ratio of wave height over block scale, HI/d', and KT, KT decreases slightly parallel with increase in HI/d', being proportional to increase in B/L. There is no significant relationship identified between Reynolds number, Re, and KT. Based on the above results, an empirical formula to assess KT is proposed, employing B/L as a parameter.

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