No abstract

Information on bowel motility can be obtained via magnetic resonance imaging (MRI)s and X-ray imaging. However, these approaches require expensive medical instruments and are unsuitable for frequent monitoring. Bowel sounds (BS) can be conveniently obtained using electronic stethoscopes and have recently been employed for the evaluation of bowel motility. More recently, our group proposed a novel method to evaluate bowel motility on the basis of BS acquired using a noncontact microphone. However, the method required manually detecting BS in the sound recordings, and manual segmentation is inconvenient and time consuming. To address this issue, herein, we propose a new method to automatically evaluate bowel motility for noncontact sound recordings. Using simulations for the sound recordings obtained from 20 human participants, we showed that the proposed method achieves an accuracy of approximately 90% in automatic bowel sound detection when acoustic feature power-normalized cepstral coefficients are used as inputs to artificial neural networks. Furthermore, we showed that bowel motility can be evaluated based on the three acoustic features in the time domain extracted by our method: BS per minute, signal-to-noise ratio, and sound-to-sound interval. The proposed method has the potential to contribute towards the development of noncontact evaluation methods for bowel motility.

The wheel surface topography in the grinding process with vitrified cBN wheels has been investigated on the basis of 3-dimensional analysis using a multi-probe SEM, and the relationships between these results and the grinding characteristic parameters have been discussed. Moreover, the change of the wheel surface profile in the grinding process has been evaluated using fractal analysis. There are two regions: an initial wear region and a steadystate wear region, in the grinding process. In the initial wear region, a rapid decrease of grinding force and a rapid increase of wheel wear occur with increasing stock removal. In the steady-state wear region, the micro self-sharpening phenomenon owing to the micro fracture as well as the attritious wear of cutting edge occurs. The change in fractal dimension of the wheel surface is closely related to the change of grinding force dominated by the wear behavior of grain cutting edges.

This paper deals with the grinding characteristics of newly developed polycrystalline cBN (cBN-U) abrasives in creep feed profile grinding of nickel-based superalloys. Experiments for producing a V-shaped groove on a flat surface in one pass by creep feed grinding have been carried out using the new polycrystalline cBN-U and representative conventional cBN (cBN-B) grits. When grinding with cBN-U abrasives, both radial wear and profile wear are less, and hence the grinding ratio is around 10 times higher than that with the conventional cBN-B abrasives. Grinding forces in grinding with cBN-U abrasives are reduced by 20-30% compared with those in Grinding with cBN-B abrasives. The cBN-U abrasive is suitable for the applications with a high dimensional accuracy in creep feed profile grinding for nickelbased superalloys, because it gives less profile wear, and hence better form retention, than conventional cBN abrasive.

The purpose of this study is to make clear the polishing characteristics of the manganese oxide slurry for wire material of Cu. To examine the polishing characteristics of the manganese oxide slurry, a series of polishing experiments for oxygen free copper have been carried out by using MnO 2 , Mn 2 O 3 and Al 2 O 3 as abrasive grains and polishing properties have been discussed. As a result, the best result among three kinds of slurries is obtained in polishing with Mn 2 O 3 slurry at the viewpoints of the stock removal and surface roughness. Furthermore polished surfaces have been analyzed using SEM and atomic force microscope. While a large number of mechanical scratches are observed in the polished surface with Al 2 O 3 slurry, the polished surfaces with manganese oxide slurries are covered with fine protrusions. It seems that the fine protrusions result from interaction between mechanical and chemical effects.