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The article discusses the initiative taken by the toilet paper industry in Japan to control flushables products to prevent house drain clogging and reduce combined-sewer overflow pollution. Topics discussed include low-flush toilet bowls sold in Japan in 1970 for water conservation, warning of the Japanese Consumer Affairs Agency to the flushable products industry against false labeling and a table depicting toilet paper disintegration test procedure.

This study aims at achieving a high speed optical disk drive for multimedia storage used in network systems. The feasibility of our target has been confirmed by the following results and techniques. High speed parallel data transfer at 336 Mbit/s in 2/7 run length limited (RLL) code or 300 Mbit/s in 1/7 RLL code has been achieved experimentally with eight beams. Focus offset has been reduced by a multibeam laser diode fabricated in junction down structure and a wide-angle lens system. Tracking error is reduced by nearly 6 dB compared with that of a conventional method. This was achieved by suppressing the mechanical interaction between the lens actuator and the beam rotation prism. The crosstalk canceler reduces both intercircuit crosstalk and optical crosstalk with pseudo crosstalk generated by a circuit. It reduces the worst-case intercircuit crosstalk by more than 14 dB.

This paper describes a new tracking technique with a multiple beam mechanism that will lead to low profile optical disk storage units with faster access speeds. In this technique, data tracking involves selection among multiple beams with minute offsets. It can accommodate four-beam laser diodes while assuring twice the tracking accuracy and ten times the tracking bandwidth of conventional approaches. Its servo performance depends on the total distance between the two outermost beams in the beam series on the medium.