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In the production process of Hard Disk Drive Magnetic Head (HDD), there is a process of writing servo signals on magCarrage & netic disks to move the head to target address. However, conventional servo track writer takes longer time to draw servo signals because of recent increase of the capacity of HDD. Therefore, they desire a low-cost method to draw servo signals. In order to resolve the problems, Self Servo Track Writing(SSTW) method which draws servo signals with its own head was already suggested. In SSTW method, Dis there are problems to realize it. One is how to know where the absolute position of head is. The other is that written servo tracks diverge because gain of the feedback controller Spindle shaft fteCoil Motor is higher than O[dB] in high frequency domain. In our past work, new method for SSTW has already Fig. 1. Overview of hard disk drive been suggested [1][2]. This method is essentially different from other methods, and performance is dramatically improved. However, servo tracks diverge gradually if we apply which were ignored il the past. this method to real product. The purpose of this paper is to make it clear why servo tracks diverge gradually by us-* It takes too much time to write servo tracks because ing Hard Disk Benchmark Software, which is produced by of higher density of servo track. Therefore, we canrt IEEJ Specialized Committee on Servo Technology for Next produce them in low cost. Generation Mass-Storage System [3]. We concluded that the produce themwil lowcst.reason is in measurement noise. Furthermore, consideration * Servo track writing process should be done ll clean for a new feedforward input is discribed. room and its maintenance is very costly. In order to solve these problems, new methods have al-

Static and dynamic centrifuge model tests, conducted to investigate mechanical behavior of buried pipes installed in sloping-sided ditches, revealed that the safety of the pipe is critical under vehicle loading applied in the static tests rather than seismic loading applied in the dynamic tests. The static tests were analyzed by using FEM, in which the soil and pipe were assumed to be linear elastic. Small frictional resistance was allowed at the interface between the pipe and the soil by introducing joint elements. Separation, slip failure, and frictional resistance were also allowed at ditch walls by introducing similar joint elements. The analysis generated results that conformed well to the test results, while the current design standards tend to underestimate the safety of the pipes. Thus, design charts for predicting the vertical deflections and the maximum bending moments of the pipes that are buried in sloping-sided ditches with different inclinations of the ditch walls were constructed by using the FEM. A thorough examination showed that the charts can be applied reasonably to any pipe (regardless of different weights, dimensions and materials), any backfill soil (regardless of different soil types, elastic coefficients and weights), and any cover height, leading to the conclusion that the charts can be used instead of the problematical current design methods.

We consider the relationship between the magnetic field and the non-elastic displacement field including defects, from the viewpoints of noncommutativity of the positions and non-commutativity of the derivatives. The former non-commutativity is related to the magnetic field by Feynman's proof (1948), and the latter is related to the defect fields by the continuum theory of defects. We introduce the concept of differential geometry to the non-elastic displacement field and derive an extended relation that includes basic equations, such as Gauss's law for magnetism and the conservation law for dislocation density. The relation derived in this paper also extends the first Bianchi identity in linear approximation to include the effect of magnetism. These findings suggest that Feynman's approach with a non-elastic displacement field is useful for understanding the relationship between magnetism and non-elastic mechanics.

RFID (Radio Frequency Identification, IC tag) technology has been put to practical use in many areas. It is expected that RFID will also be used in designing or developing new recycling systems or in managing waste materials. We suggest that the technology using IC tags, which are able to store a relatively great amount of data related to the specification of the materials, can be used in various recovery or separation processes and be used at the surface contamination condition. Such a process can be effective since it not dependent of the physical properties of the materials to be processed. At first, the use of a microwave type IC tag, mounted on artificial parts to be separation, was investigated as a function of the speed and distance from the IC tag data reader. Next, if IC tags are utilized for the parts reuse and store of automobiles in order to increase the material recycling rate. Moreover, the environmental burden for automobile recycling has also been discussed. Figure 1 The concept of IC tag utilization for sorting the parts of the wasted electric appliances and machines.