Method for Identifying Type of Eddy-Current Displacement Sensor

Eddy-current (EC) displacement sensors are used in a device for measuring the shaft vibration of turbines. An EC displacement sensor is composed of a sensor probe and an impedance/output voltage (Z/V) converter. In a power plant in the U. S., the type of the sensor probe and the displacement from the turbine shaft to the tip of the sensor probe (displacement x) are not controlled. For this reason, when only the Z/V converter breaks down, the plant is stopped and dismantled, and both the Z/V converter and the sensor probe are replaced. This results in two problems, i.e., the unstable supply of electric power when the power plant is stopped and the high cost of dismantling the plant. If both the type of the sensor probe and x are identified during turbine operation, the aforementioned problems could be solved. In this paper, we describe that the three types of the sensor probe and x can be identified by comparing the measured the maximum quality factor Q(EC) (max) and frequency f(o) at Q(EC) (max) with the Q(EC) (max) versus f(o) characteristics of sensor probes.ArticleIEEE TRANSACTIONS ON MAGNETICS. 47(10):3554-3557 (2011)journal articl

Cellular Orientation on Repeatedly Stretching Gelatin Hydrogels with Supramolecular Cross-Linkers

The cytocompatibility of biological and synthetic materials is an important issue for biomaterials. Gelatin hydrogels are used as biomaterials because of their biodegradability. We have previously reported that the mechanical properties of gelatin hydrogels are improved by cross-linking with polyrotaxanes, a supramolecular compound composed of many cyclic molecules threaded with a linear polymer. In this study, the ability of gelatin hydrogels cross-linked by polyrotaxanes (polyrotaxane–gelatin hydrogels) for cell cultivation was investigated. Because the amount of polyrotaxanes used for gelatin fabrication is very small, the chemical composition was barely altered. The structure and wettability of these hydrogels are also the same as those of conventional hydrogels. Fibroblasts adhered on polyrotaxane–gelatin hydrogels and conventional hydrogels without any reduction or apoptosis of adherent cells. From these results, the polyrotaxane–gelatin hydrogels have the potential to improve the mechanical properties of gelatin without affecting cytocompatibility. Interestingly, when cells were cultured on polyrotaxane–gelatin hydrogels after repeated stress deformation, the cells were spontaneously oriented to the stretching direction. This cellular response was not observed on conventional hydrogels. These results suggest that the use of a polyrotaxane cross-linking agent can not only improve the strength of hydrogels but can also contribute to controlling reorientation of the gelatin