The impact of divorce precedents on the Japanese divorce rate

This paper undertakes a time series analysis of the Japanese divorce rate using annual data over the period 1964–2006. One of the key innovations of the paper is to use court decisions on divorce disputes to construct an index that seeks to measure how the probability of success in a divorce suit has changed over time. The computed index suggests that if it is the culpable party lodging the divorce suit, the probability of the suit being successful has clearly increased over time. The probability of winning a divorce suit appears to be an important factor in explaining the long-run rise in the Japanese divorce rate. The divorce rate also appears to be counter-cyclical.     

Seismic proof test of a reinforced concrete containment vessel (RCCV): Part 1: Test model and pressure test

In Japan, the Nuclear Power Engineering Corporation (NUPEC), sponsored by the Ministry of Economy, Trade and Industry (METI), has been conducting a series of seismic reliability proving tests using full-scale or close to full-scale models to simulate actual important equipment that is critical for seismic safety of nuclear power plants. The tests are intended to validate the seismic design and reliability with a sufficient margin even under destructive earthquakes. A series of tests was carried out on a reinforced concrete containment vessel (RCCV) for advanced boiling water reactor (ABWR) from 1992 to 1999. A large-scale high-performance shaking table at Tadotsu Engineering Laboratory, the largest in the world, was used for this test. Part 1 reports the test model and the results of pressure and leak tests. Part 2 describes test procedures, input waves and the results of verification tests such as changes of stiffness, characteristic frequency and damping ratio, the failure of the model and the load deflection. Part 3 shows the seismic safety margin that was evaluated from the energy input during the failure test to a design basis earthquake. Part 4 reports simulation analysis results by a stick model with lumped masses.     

A monolithic InP/SOI platform for integrated photonics

The deployment of photonic integrated circuits (PICs) necessitates an integration platform that is scalable, high-throughput, cost-effective, and power-efficien...     

Design and manufacturing of JT-60SA vacuum vessel

JT-60 is planned to be upgraded to JT-60SA tokamak machine with fully superconducting coils, which is a project of the JA-EU satellite tokamak program under both Broader Approach program and Japanese domestic program. The JT-60SA vacuum vessel (VV) has a D-shape poloidal cross section and a toroidal configuration with 10° facet segmented in toroidal direction. The material of the VV is 316L stainless steel with low cobalt content of <0.05 wt%. A double wall structure is adopted for the VV to ensure high rigidity and high toroidal one-turn resistance simultaneously.Fundamental welding R&D and a trial manufacturing of the 20° upper half of the VV have been performed to study the manufacturing procedure. After the confirmation of the quality of the mock-up, manufacturing of the actual VV started in November 2009.     

Fundamental welding R&D results for manufacturing vacuum vessel of JT-60SA

The real vacuum vessel (VV) manufacturing of JT-60SA has started since November 2009 at Toshiba. Prior to starting manufacturing, fundamental welding R&Ds had been performed by three stages. In the first stage, primary tests for screening welding method were performed. In the second stage, the trial welding for 1 m-long straight and curved double shell samples were conducted. The dependences of welding quality and distortion on the welding conditions, such as arc voltage and current, setting accuracy, welding sequence, and the shape of grooves were studied. In addition, welding condition with low heat input was explored. In the last stage, fabrication sequence was confirmed and established by the trial manufacturing of the 20° upper half mock-up [1]. This paper presents the R&D results obtained in the first and second stages.     

Thermodynamics of antimony,arsenic, and tin in CaO—CaF2 melts

In view of the importance of tramp element contamination of steel products through a large volume of scrap consumption in the near future, the thermodynamic behaviour of Sb, As, Sn and Cu in CaO—CaF₂ melts under reducing conditions was studied by examining the dependences of distribution of each element between Cu, Ag or Sn alloys and CaO—CaF₂ melts on the CaO activity, oxygen partial pressure and temperature around 1 500°C. As a result, the reaction products on treatment by Ca compounds were demonstrated to be Ca₃Sb₂, Ca₃As₂, Ca₂Sn and CaCu. Experimentally obtained distributions were extrapolated to lower oxygen partial pressures less than 10^?18 atm to estimate the feasibility of removing those tramp elements from molten iron. It is thermodynamically indicated that if the prevailing oxygen partial pressure of the environment is below 10^?23 atm, these impurities, except Cu, would be substantially removed from molten steel.     

Aseismic evaluation for aging degradation of nuclear power plant components

The commercial operation of light water reactor plants in Japan already has a history of nearly 30 years. Since the beginning of the 1990s, studies have been conducted on aging degradation of nuclear power plants in Japan and abroad and, earlier in 1999, the domestic program of plant life management (PLM) was settled on. The program is based on the results of the PLM Study, which started in 1997. The purpose of the study was to develop the preventive maintenance program with an evaluation of aging degradation for maintaining the functions of plant component equipment. Taking account of the need for proper management of aging degradation, meanwhile, the technical evaluation of aseismic capability of aged plants is also considered to be important. Based on this concept, we evaluated the impact of assumed aging degradation on the aseismic capability of the plant facilities and structures covered by the PLM Study. In the aseismic evaluation, aging degradation modes selected in the PLM Study were divided into two categories—the one is including some degradation modes which impact on the aseismic capability of the facilities and structures should be taken into account, the other is including those whose impact might be ignored. Then the aging degradation modes composing the former one were quantitatively evaluated primarily based on the Technical Guidelines for Aseismic Design of Nuclear Power Plants (JEAG-4601) (NUREG/CR-6241, 1987). The result of the evaluation indicated that no aging degradation mode to be reflected in the maintenance program was extracted from the viewpoint of securing the aseismic capability of the plant components. However, establishment of rational evaluation methods for aging degradation, e.g. aseismic capability evaluation of thinned piping systems, was made a future technical subject.     

A decentralized control system for stabilizing multimachine power systems

A decentralized control system is studied for stabilizing multimachine power systems. A longitudinal power system with three areas, each having one machine, is considered in this study. A decentralized control design method is proposed, which is based on the optimal regulator theory. First a centralized control system is designed without any consideration on whether state variables are all available or not. Second a pseudo-decentralized control system is designed by omitting control gains corresponding to state variables which give hardly any effects on the power system stability. It is found that only one variable of phase angle of each machine is absolutely necessary for the pseudo-decentralized control system. This leads to an idea based on power system engineering, that is to say, new variables of tieline power flow are introduced in the decentralized control system design to substitute for the phase angle of each machine. Thus a decentralized control system for power system stability can be designed using the new variables of tieline power flow. It is demonstrated from simulation studies that the decentralized control system improves even longitudinal power system stability as well as the centralized control system.     

Photo-induced radicals in glucose and cellobiose

Photo-induced radicals in glucose and cellobiose, the model compounds of cellulose molecule, were studied by ESR spectrometry. Very poor formation of radicals in glucose as compared to those in cellobiose was observed. However, a spectrum showing a singlet line was easily produced by the use of light involving shorter wavelengths. It was estimated to be due to the radical formed at the reducing C₁ position of glucose molecule. By paper chromatography, the photo-irradiated cellobiose was confirmed to split into glucose through scission of glucosidic bonds in the molecule. The ESR spectrum of the acid-hydrolyzed cellulose similar to that of the unhydrolyzed sample was a seven-line spectrum, but the relative signal intensity was here markedly low. This phenomenon seems to be caused by the reduction of amorphous portion in the samples due to acid hydrolysis. It was concluded that the glucosidic bonds in cellobiose and cellulose molecules are very active toward light and play an important role in the radical formation in photo-irradiated samples.     

In-line type micropulse lidar with an annular beam: experiment

An in-line type compact micropulse lidar (MPL) with an annular beam was developed for low-altitude cloud measurement. An optical circulator and a couple of axicon prisms for an annular beam were installed on the lidar optics. The advantage of using the in-line MPL is its ability to obtain a near-range measurement with a narrow field of view of 0.1 mrad and to obtain a depolarization measurement of the orthogonally polarized echoes caused by ice crystals of a low-altitude cloud. The total insertion loss of the lidar optics was 3 dB. Detectors such as avalance photodiode detectors can be operated in an analog mode near the breakdown voltage because of the high isolation of the optical circulator. The ideal lidar echo variation from the nearest distance was verified by measuring the mountain echoes at various distances. The depolarization measurement of a low-altitude ice cloud was also demonstrated.