Preparation of CdS-doped Glasses from Gels Containing Diethyldithiocarbamatocadmium

CdS-doped SiO₂ glasses were prepared via silica gels containing diethyldithiocarbamatocadmium Cd(S₂CN(C₂H₅)₂)₂. Heat treatment of the gels gave transparent yellow SiO₂glasses doped with hexagonal CdS crystals. In optical absorption and fluorescence spectra, the optical absorption edge and the emission peak clearly exhibited a blue shift, which was attributed to the quantum size effect of the carrier confinement, as the CdS content was decreased. In the fluorescence spectra of the CdS-doped silica glasses, the emission peak was observed only near 500 nm and not observed at longer wavelengths which were known to be present if there were sulfur vacancies.     

Building a CIM system for compound plant: Utilization of distributed processing system

The position of a production management system in a computer-integrated manufacturing (CIM) system is to serve as the nucleus of the plant CIM system that connects the plant production to other departments such as marketing, research and development, and distribution departments. A production management system that integrates the flow of goods with information in a plant, and thus manages production in it, was developed as the first step toward application of CIM to a powder plant. The method of building a distributed system is one way to build a CIM system. This method creates a system in the required function units, which are connected by a network to expand the system function. It offers advantages in extensibility, flexibility, and rapid implementation.     

Effects of External Stress on Defect Annihilation and Bubble Swelling During Annealing of Neutron-Irradiated Silicon Carbide

Silicon carbide ceramics fabricated by three different methods were neutron-irradiated in the Japan Materials Testing Reactor and were subsequently annealed free from stresses or under compressive external stresses. The macroscopic length monotonically decreased with annealing above the irradiation temperature, when annealing was performed below ∼1300°C. This decrease was not affected by the external stresses. However, annealing above ∼1300°C led to an increase in length in B-containing SiC. The expansion was caused by the formation and growth of He bubbles at grain boundaries. The growth occurred by flow of vacancies into bubbles. The compressive stress retarded the expansion along the loading direction. This retardation was compensated by a length incrase along the lateral direction. The effect of external stresses was discussed by considering differently oriented He bubbles. One bubble was stress favored and the other stress unfavored. The stress determined the diffusional flow of vacancy-He atom complexes between the favored and unfavored bubbles which were caused by anisotropic expansion under a directional stress.     

Time Varying Deadbeat Control Of High Order Chained Systems

A new digital control method for a time varying sampled data system called a time varying deadbeat control is proposed for the control of high order nonholonomic chained systems with drift terms. This control law has the potential to avoid excessive overshoot and prevent trajectories from getting close to the singular manifolds of the transformation needed to obtain the chained forms.     

Optimal facility location with multi-purpose trip making

We address the optimal location problem for two different types of service, designated as type-A and type-B, where some users may obtain both types of service in multi-purpose trips. We consider three user groups: (i) users of only the type-A service; (ii) users of only the type-B service; and (iii) users of both services in a single trip. We seek to locate three types of facilities: (i) type-A; (ii) type-B; and (iii) joint facilities that offer both services. We formulate a p-median-based model that minimizes the total travel distance and use it to investigate the effect of multi-purpose trip-makers on optimal facility types and locations. Examples are used to show that services tend to cluster in joint facilities, even when the proportion of multi-purpose behavior is small.     

Experimental studies on ice shells in Asahikawa

An ice shell is thin, and its structural material is snow-ice. It may be an efficient form of instant shelter for snowy and cold regions. This paper describes two field studies on ice domes carried out in Asahikawa. The first one is an investigation on the creep collapse of a 5-m span model under a concentrated load acting on a circular area at the apex. Normal displacements and temperatures were measured up to the collapse. Experimental collapse time was examined, introducing the classical creep buckling value of a completely spherical shell under uniform external pressure. The second study deals with both the construction technique and the creep test of a 10-m span model. The construction technique consists of: (1) inflating a membrane bag covered with rope, (2) spraying it with snow and water, (3) solidifying the snow-ice sherbet on it, and (4) removing the bag and rope for reuse. Subsequently, a creep test was carried out under snow load, and its structural behaviour up to the collapse was examined. Based on the results of these studies, the production of 20–30-m span ice shells may be practicable.     

Statistical analysis of lightning performance of distribution lines based on observation in fields

Because of the lower insulation level than for transmission lines, in this study on lightning protection design of distribution lines, not only direct lightning strokes but also induced voltages caused by nearby strokes must be taken into account. Thus, it is necessary to grasp the frequency of occurrence of lightning phenomena around distribution lines. For this aim, lightning phenomena on TEPCO's distribution lines in use were continuously observed for 6 years (1996 to 2001). Through this observation, new interesting statistical data that can be a useful basis for rationalization of lightning protection design of distribution lines were obtained. Two hundred and four lightning strokes were observed through the six‐year period. Probability of occurrence of a direct stroke was 22% (45 direct strokes were obtained). The fact that in 47% of direct strokes the electric outage did not occur is very interesting. Moreover, the value of surge discharge current of the arrester in the case of nearby stroke is the basis for conventional theory of grounding system. Therefore, statistical analysis of ZnO discharging current in the case of nearby strokes was carried out. As a result, in the case of nearby strokes, 5% value of cumulative frequency of discharging current is 0.5 kA. This value is half the conventional data. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(2): 8–16, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20180