Boson peak and structural heterogeneity in ternary SiO2-Al2O3-B2O3 glasses

We use low-temperature heat capacity, low-frequency Raman scattering, and THz time domain spectroscopy in order to scale the vibrational density of states and the Boson peak in SiO₂-Al₂O₃-B₂O₃ Yb-laser host glasses. When substituting B₂O₃ for SiO₂ at constant Al₂O₃ dopant level, we find an optimal value for the ratio of B/Al in terms of mixture stability, at which the excess in the electron donor capability of Al₂O₃ (relative to the SiO₂ backbone) is compensated by the more acidic B₂O₃. At this composition, Al₂O₃ plays a mediating role in the structure of aluminoborosilicate glasses, facilitating dissolution of Yb₂O₃ and admixture of B₂O₃ into the SiO₂ network.     

Evaluation of standing‐sitting support system with passive rotational seat mechanism in standing motion

Since a decrease in muscle mass of elderly people, the physical burden of them in standing‐sitting motion of a seat are increasing than young people. For this problem, several standing‐sitting support systems have been developed, and evaluations of these systems focusing on a reduction of physical load have been discussed. However, these evaluations are of support systems with an active actuators or of support systems when they use a handrail and a standing aid. Thus, an evaluation of a support system with only passive actuators has not been reported. In this paper, in standing motion with using a standing‐sitting support system with passive rotational seat mechanism which our group proposes, we objectively evaluate an effectiveness of the passive rotational seat mechanism by statistical analysis.     

Production of Gentiobiose from Hydrothermally Treated Aureobasidium pullulans β-1,3-1,6-Glucan

We report production of the functional disaccharide gentiobiose β-D-Glcp-(1→6)-D-Glc by a hydrolysis reaction of hydrothermally treated Aureobasidium pullulans β-1,3-1,6-glucan as the substrate and Kitalase as the enzyme. Gentiobiose was produced over the pH range 4−6 and the concentration of gentiobiose produced decreased above pH 7. The maximum value of gentiobiose production was unaffected by the enzyme concentration. The maximum concentration of gentiobiose produced was dependent on the substrate concentration whereas the maximum ratio of gentiobiose to glucose was not. The production of gentiobiose from yeast β-1,3-1,6-glucan was lower than that from A. pullulans β-1,3-1,6-glucan.     

Predictive Simulation of Deformation and Failure of Peat-Calcareous Soil Layered Ground Due to Multistage Test Embankment Loading

The continuous behaviour of a ground-embankment system from the stage of deformation up to failure was predicted with respect to an actual test embankment that had been constructed in stages on a soft ground made up of peat and calcareous soil. The behaviour prediction was carried out by employing soil-water coupled finite deformation analysis, which also included simulation of the embankment construction process. The information used in the analysis was limited to such things as the results of soil tests on soil materials (peat and calcareous soil) sampled from the ground, including their sensitivity ratios, and the embankment's construction history. The SYS Cam-clay model was used in the constitutive equations of the soils to determine the material constants of the soils and the initial conditions of the ground, and the computations were performed under plane strain conditions. As a result, the computed profiles of W-type ground settlement and of slip surfaces running through the embankment were found to be in good overall agreement with the actual profiles measured at the site. Furthermore, we found that this slippage is attributable to the undrained shear response of the soil elements in the calcareous soil layer, where slippage begins to occur during embankment loading. In other words, the slippage is caused by the rapid softening behaviour caused by the degradation of structure after the effective stress ratio reaches the vicinity of the critical state line.     

Use of a Metal-mould Process in the Development of Hemispherical Heavy-walled Castings

The exacting quality required of hemispherical heavy-walled steel castings, used in nuclear power applications, has been remarkably improved by the adoption of a newly developed metal-mould process. This technique is dependent on the use of a metal core. The optimum conditions for solidification were determined by the finite element analytical method. The appropriate wall-thickness of the chill elements was also investigated using data based on actual experience. The core was designed in such a manner that the surface carried a series of concave “dimples” in the manner of a golf-ball, the pattern being intended to prevent the formation of cracks, generated on the casting surface when in contact with a metal mould. Stresses caused by solidification shrinkage were reduced by splitting the core. In the event, the casting structure conformed well to the results of the solidification analysis. Radiographic examination revealed a high level of soundness, with no trace of internal defects. No anisotropy was detected in mechanical properties. It is shown that this process is being currently employed in the manufacture of actual products.