Stress Corrosion Cracking Behavior at Inconel and Low Alloy Steel Weld Interfaces

Three-dimensional microstructure observations, macro- to micro-scopic residual stress measurements by three methods and creviced bent beam SCC tests were performed for Inconel/low alloy steel (LAS) weld samples. The possible reasons for the suppression of SCC crack propagation near the weld interface found at a nuclear power plant were estimated to include the crack branching at the grain boundary (GB) parallel to the interface, i.e., Type II GB, compressive residual stresses in the LAS region and crack tip oxidation in the LAS at the interface. The formation mechanism of Type II GB and stress gradient in individual grains in the Inconel are also discussed.     

Study on high thermal conductivity of mesogenic epoxy resin with spherulite structure

The microstructure of a mesogen-containing epoxy resin that exhibits high thermal conductivity (0.33 W/m K) was investigated by observations of the scanning electron microscope (SEM) and the polarized optical microscope (POM). It was found that there are many spherulite structures formed in the resin. We supposed that the reason for the high heat-conductivity obtained in the resin is ascribed to the existence of the spherulite morphology where highly ordered lamellar structures aggregated. The argument was strongly supported by preparing the resin films with size-changed spherulites which are induced by changing the initial curing temperature. The result revealed that the thermal conductivity increased with the increase in spherulite size. On the other hand, we have developed the spherulite size in the resin from 10 to 80 μm in diameter that resulted in a greatly improved thermal conductivity of up to 1.16 W/m K in the highest value. This study may provide a useful method to improve the thermal conductivities of mesogenic resins themselves by producing spherulite structures.     

Inverse subsumption for complete explanatory induction

Modern explanatory inductive logic programming methods like Progol, Residue procedure, CF-induction, HAIL and Imparo use the principle of inverse entailment (IE). Those IE-based methods commonly compute a hypothesis in two steps: by first constructing an intermediate theory and next by generalizing its negation into the hypothesis with the inverse of the entailment relation. Inverse entailment ensures the completeness of generalization. On the other hand, it imposes many non-deterministic generalization operators that cause the search space to be very large. For this reason, most of those methods use the inverse relation of subsumption, instead of entailment. However, it is not clear how this logical reduction affects the completeness of generalization. In this paper, we investigate whether or not inverse subsumption can be embedded in a complete induction procedure; and if it can, how it is to be realized. Our main result is a new form of inverse subsumption that ensures the completeness of generalization. Consequently, inverse entailment can be reduced to inverse subsumption without losing the completeness for finding hypotheses in explanatory induction.     

A Computational Study of Contact Mechanics between Magnetic Recording Heads and Thin-Film Disks

The tribological phenomena between magnetic head sliders and thin-film disks are studied during rest, during start-up and shutdown, and during regular operation using numerical simulations. A theoretical model of stiction is first derived based on the surface tension of liquid and capillary condensation. Next, a hybrid method of FEM and BEM is developed in order to carry out high-precision microscopic contact stress analysis of a disk covered by multilayer thin films. An impact simulator based on FEM is then presented which considers the air lubricant film to be an elastic spring system determined from the solution of a compressible Reynolds equation, ft is found, that these simulators can be used to effectively study the tribology of slider/disk interactions and that the results can be used to establish qualitative design criteria for slider/disk mechanisms.     

A neural decoding approach to auditory temporal assimilation

By constructing Gaussian Naïve Bayes Classifiers, we have re-analyzed data from an earlier event-related potential (ERP) study of an illusion in time perception known as auditory temporal assimilation. In auditory temporal assimilation, two neighboring physically unequal time intervals marked by three successive tone bursts are illusorily perceived as equal if the two time intervals satisfy a certain relationship. The classifiers could discriminate whether or not the subject was engaged in the task, which was judgment of the subjective equality between the two intervals, at an accuracy of >79%, and from principal component scores of individual average ERP waveforms, we were able to predict their subjective judgments to each stimulus at an accuracy of >70%. Chernoff information, unlike accuracy or Kullback–Leibler (KL) distance, suggested brain activation associated with auditory temporal assimilation at an early pre-decision stage. This may provide us with a simple and useful neural decoding scheme in analyzing information processing of temporal patterns in the brain.