Evaluation of liquefaction probability of earth-fill dam over next 50 years using geostatistical method based on CPT

A method for evaluating the liquefaction probability of an earth-fill dam over the next 50 years is presented through the use of a geostatistical method for the measured values from cone penetration tests (CPTs). In particular, this paper discusses a new procedure for evaluating the liquefaction probability based on CPTs. Although the fines content, F_c, and the N-value are required in the Japanese standards to evaluate the liquefaction risk, the number of test data is not enough for the statistical modeling. Herein, F_c and the N-value are derived directly from CPTs. The statistical modeling procedure for F_c and the N-value is the unique point of this study. Since CPTs can be conducted with short intervals, especially in the horizontal direction, the geostatistical parameters can be determined, and the geostatistical simulation method is applicable for evaluating the liquefaction probability. In addition, since the frequency of the seismic load at the studied site will affect the liquefaction probability, the seismic hazard should be evaluated properly. An illustrative example, assessing the liquefaction probability of an earth-fill dam in Japan, is presented to demonstrate the capability of the proposed method. Finally, the spatial average of the liquefaction probability of the dam over the next 50 years is calculated. The proposed procedure is confirmed to work well for actual design problems.     

Guided-wave optical gate matrix switch

An optical gate matrix switch that is made by integrating InGaAsP laser diode gates with high-silica guided-wave splitter and combiner circuits in a hybrid fashion is proposed and demonstrated. It provides point-to-multipoint switching. A preliminary experiment for a 4×4 matrix switch shows that the switch is capable of more than 400-Mb/s bandwidth signal switching     

Quantification of ternary mixtures of heavy metal cations from metallochromic absorbance spectra using neural network inversion

A new method based on artificial neural networks (ANN) for the processing of spectrophotometric data is proposed and illustrated on the example of the simultaneous quantification of ternary mixtures of zinc, cadmium, and mercury cations in aqueous solutions. Three types of commercially available metallochromic indicators were used as a simple model setup to create spectral data analogous to those normally received from an optical sensor array. In conventional ANN training methods for chemical sensors based on spectrophotometric data, a calibration is established by mathematically correlating the measured optical signal as network input with the concentration of the calibration sample as network output. In several situations, however, especially when dealing with mixed sample solutions, the relationship between a measured absorption spectrum and the corresponding ion concentrations is ambiguous, resulting in an "ill-posed problem". On the other hand, if the training direction is reversed by correlating known sample concentrations with measured optical signals, the relationship becomes reasonable for the ANN to obtain its structure. The proposed model illustrated in this paper is based on a more reasonable direct mapping and estimation by artificial neural network inversion (ANNI). In the training step, sample mixtures of known concentrations are optically measured to construct networks correlating the input data (ion concentrations) and the output data (absorption spectra). In the estimation step, the ion concentrations of unknown samples are estimated using the constructed ANN. The measured spectra of the unknown samples are fed to the output layer, and the appropriate input concentrations are determined by ANNI. When training the ANN system with 143 ternary mixtures of Zn2+, Cd2+, and Hg2+ in a concentration range from 1 to 100 microM, root-mean-square errors of prediction (RMSEP) of 0.45 (Zn2+), 0.96 (Cd2+), and 0.32 microM (Hg2+) were observed for the estimation of concentrations in 30 test samples, using the ANNI procedure. This newly proposed model, which involves the construction of an ANN based on direct mapping and estimation by ANNI, opens up one way to overcome the limitations of nonselective sensors, allowing the use of more easily accessible semiselective receptors to realize smart chemical sensing systems.     

A novel hydroxylase from Catharanthus roseus participating in the hydroxylation of 2-hydroxybenzoic acid

A novel 55-kDa hydroxylase was isolated from cultured cells of Catharanthus roseus by a three-step procedure: anion exchange chromatography, affinity chromatography and hydroxylapatite adsorption chromatography. The enzyme specifically catalyzed the hydroxylation of 2-hydroxybenzoic acid to give 2,5-dihydroxybenzoic acid. The enzyme activity was optimal at pH 7.8 and was completely inhibited by divalent cations, such as Cu(2+) and Hg(2+). The enzyme showed sequence similarity to certain plant flavonoid 3'-hydroxylases.     

Film-level hybrid integration of AlGaAs laser diode with glasswaveguide on Si substrate

A ridge-waveguide AlGaAs laser diode (LD) was integrated with a SiO₂-Ta₂O₅ embedded waveguide on a Si substrate by using a film-level hybrid integration technique of semiconductor epitaxial film. CW operation of the LD was achieved at room temperature. The LD-waveguide butt-coupling loss was 9 dB, and the loss due to misalignment was estimated at 3 dB, which corresponds to a displacement of about 1 μm in both the vertical and lateral directions     

Deoxidation of molten titanium by electron-beam remelting technique

The deoxidation of molten titanium was attempted by aluminum suboxide evolution in an electron-beam remelting furnace. Titanium aluminum alloy was deoxidized to about 0.05 to 0.01 wt pct oxygen in a few minutes by adding aluminum to the melt. Aluminum activity in the alloy was estimated by the evaporation rate of aluminum. formerly Graduate Student, Institute of Industrial Science, The University of Tokyo     

Development of a Custom LSI for Industrial Data Communication

A new custom LSI for industrial data communication systems has been developed. This LSI provides all of the functions required for data communication between control equipment and plants without any additional circuits or software. It is also versatile enough to be adaptable to many kinds of industrial control systems.     

2 × 2 optical waveguide matrix switch using nematic liquid crystal

A 2 × 2 nonblocking optical matrix switch, composed of four elemental switches formed in a slab waveguide, is described. Switching action is based on total internal reflection caused by an electrically controlled change in refractive index of the liquid crystal. Propagation loss was remarkably reduced to 2.3 dB/cm, both by using liquid crystal as a cladding layer and by operating at the 1.31 μm wavelength. The experimental matrix switch exhibited 7.3-7.7 dB insertion loss, -17.3 to -18.2 dB crosstalk, and a 14° switching angle.     

Readout characteristics of a non-circular aperture mounted on an optical head slider flying above a medium having sub-100-nm-long patterns

The near-field principle combined with thin-film gas-lubricated slider bearing technology is thought to be one of the most promising breakthroughs to overcome the difficult optical diffraction limit (or wavelength shortening limit), which governs traditional optical recording performance. In light of this, we have demonstrated high linear density (150 nm pattern length) and high speed 10 MHz readout signals using the combination of a tapered circular aperture and a planar lens mounted on a quartz slider, flying above a metal patterned medium. In order to further improve both the spatial resolution and signal-to-noise ratio of this device, it is essential to minimize the spacing and laser power throughput of an aperture. Also investigated was the effectiveness of a non-circular aperture, which has approximately triangular configuration in combination with polarized light in simultaneously improving spatial resolution and increasing signal output. In this paper, we confirmed the predicted effectiveness on more practical condition of both high speed and compactness of head construction using a sub-micrometer size non-circular aperture, which was mounted on a 1.5-mm-long miniaturized optical head slider, flying above a ROM medium having sub-100-nm-long chromium patterns. The influence of the electric-field direction of the incident light and aperture to medium spacing on the readout signal are carefully evaluated by flying the aperture at spacing down to less than 50 nm.     

New magnetic implant material for interstitial hyperthermia

Magnetic properties and heat generation characteristics of a bio-compatible ceramic Mg_1+xFe_2–2xTi_xO₄ system have been investigated as an implant material for the magnetic induction hyperthermia. Curie temperature (T_c) of the ceramic decreases with increasing x; and become T_c, 350 K at x ç0:35 and, 315 K at x ç 0:38; which is suitable Curie temperature for implant material. The temperature of ceramic as a function of time under the high frequency alternating magnetic field is self-controlled at T_c.

The surface temperature of a powder injection sphere cancer model, which was a mixture of the agar phantom and the ceramic powder implant, and the temperature distribution around the sphere set in the pure agar phantom matrix have been measured. The result is in good agreement with calculation using a finite element method (FEM). It was found that the temperature distribution inside of the sphere and the minimum quantity of Mg_1+xFe_2–2xTi_xO₄ necessary for hyperthermia could be estimated by the FEM calculation.