Detection of Damaged Distribution Surge Arresters Using an Impulse Generator

Distribution surge arresters with an internal series gap have been installed on Japanese distribution lines at high density to reduce lightning‐related overvoltages. In contrast, surge arresters are sometimes damaged by direct lightning strokes, particularly in winter. Measurement of the insulation resistance between the terminals of the surge arrester and measurement of the dc discharge voltage of the surge arrester are generally adopted to detect damaged arresters. However, if metal‐oxide (MO) varistors are damaged and the internal series gap is not damaged, it is difficult to detect damaged arresters by the two conventional methods. Therefore, this paper presents a proposed detection method that can accurately detect damaged arresters. In the proposed method, first, the voltage between the terminals of the surge arrester is measured when the output of an impulse generator is applied to the surge arrester. Second, the damaged arrester is detected by comparison between its voltage waveform and the voltage waveform of the nondamaged arrester. The detection rate of damaged arresters by the proposed method is markedly higher than the rates of detection by the two conventional methods.     

Genetic algorithm approach to a production ordering problem in an assembly process with constant use of parts

An optimal production scheduling problem for an assembly process with buffers at the input and output sides of a machine is dealt with. The problem has two kinds of constraints. One constraint is that the buffers' capacity is limited. The other constraint is that the cycle time of the worker is constant without waiting time. An optimal production ordering is determined, subject to these constraints, in such a way that the rate of use of parts to produce each product should be as constant as possible. A procedure to apply the genetic algorithm to this problem is shown. The operations of reproduction, crossover and mutation are presented. It is observed from numerical results that the genetic algorithm gives a better suboptimal solution than the greedy method.     

Influence of the microenvironment on gene and protein expression of odontogenic-like and osteogenic-like cells

Progenitor cells play an important biological role in tooth and bone formation, and previous analyses during bone and dentine induction have indicated that they may be a good alternative for tissue engineering. Thus, to clarify the influence of the microenvironment on protein and gene expression, MDPC23 cells (mouse dental papilla cell line) and KUSA/A1 cells (bone marrow stromal cell line) were used, both in vitro cell culture and in intra-abdominal diffusion chambers implanted in 4-week-old male immunodefficient mice (SCID mice). Our results indicate that KUSA/A1 cells differentiated into osteoblast-like cells and induced bone tissue inside the chamber, whereas, MDPC-23 showed odontoblast-like characteristics but with a low ability to induce dentin formation. This study shows that MDPC-23 cells are especial cells, which possess morphological and functional characteristics of odontoblast-like cells expressing dentin sialophosphoprotein in vivo. In contrast, dentin sialophosphoprotein gene and protein expression was not detected in both cell lines in vitro. The intra-abdominal diffusion chamber appears as an interesting experimental model for studying phenotypic expression of dental pulp cells in vivo.     

High-pressure synthesis of diamond from phenolic resin

Two kinds of phenolic resin, novolak and resols, have been studied with an addition of cobalt at pressures between 2 and 4 GPa and at temperatures from 1300 to 1900 °C, all under thermodynamically graphite-stable conditions. Diamond was synthesized from these resins which had been pre-fired at 500–1000 °C. From such resins, carbon precursors carrying a great number of radicals, being nearly free of hydrogen and oxygen, and turbostratic in structure, can be constructed. The pressure–temperature conditions suitable for the diamond synthesis were dependent on the pre-firing temperatures. The cobalt served as a catalyst–solvent, similar to the case of conventional diamond synthesis from graphite under diamond-stable conditions. Well-defined single crystals cubo-octahedral in shape, measuring 0.3–0.7 mm across and classified as type Ib were obtained. This revised version was published online in November 2006 with corrections to the Cover Date.     

SAFETY EXAMINATION OF SOME EDIBLE OR MEDICINAL PLANTS AND PLANT CONSTITUENTS, PART 3

The carcinogenicity of vicia, galanga, lathyrus and lycium, which are plants used as human food or in folk medicine, and of caffeic acid and prunasin, which are plant constituents, was examined in an inbred strain of ACI rats. Fresh plant materials were dried, milled and mixed with the rat basal diet in the ratio of 16% and 33% of the total. The plant constituents, caffeic acid and prunasin, were mixed with the basal diet in the ratio of 0.5% and 0.03%, respectively. These diets were administered to rats for periods ranging upward from 180 days. Carcinogenic activity was not observed with any of the plants or plant constituents.     

Protein Content in Milk by Near-Infrared Spectroscopy

A corrected equation for the determination of protein content in oil/ water emulsions, developed previously, was applied for determination of protein content in milk and standard errors were satisfactory for the determination. This corrected equation can be used for determination of protein content in milk.     

Sapid Components in Carrot

SUMMARY: The relationship between various substances present in carrot to its taste was studied. Nucleic acid derivatives found in hot water extracts of carrot were adenine, adenosine, inosine, hypoxanthine, 5'-AMP, 5'-UMP, UDP, but 5'-IMP and 5'-GMP were absent. The contents of these derivatives were extremely small. Silica gel chromatography showed the presence of small quantities of succinic acid, α-ketoglutaric acid, lactic acid, pyroglutamic acid, citric acid and glycolic acid.
Amino acids in hot water extracts of carrot were detected by two-dimensional thinlayer chromatography and automatic amino acid analyzer. Identified were glutamic acid, valine, leucine, aspartic acid, lysine, and serine etc. Glutamic acid content was relatively large. Sucrose, maltose and glucose were detected in carrot and these carbohydrates were responsible for the sweetness of carrot. The taste of carrot was due mainly to the presence of glutamic acid and the buffer action of various amino acids.     

An autonomous decentralized scheduling algorithm for a scheduling problem in a metal mould assembly process

This paper deals with a scheduling problem in a metal mould assembly process. The process is of job shop type with several additional constraints. One constraint is that precedence relations exist not only among operations but also among jobs. The other constraint is that the system has two types of machines in parallel. The single-function machine executes a specific operation of each job and the multi-function machine can execute several operations. Therefore selection of the machine is necessary for executing each operation. In addition the problem has two objective functions. One is to minimize the sum of the tardiness of each job, and the other is to maximize the working time of the multi-function machine because of reducing the operating cost of machines. An autonomous decentralized scheduling algorithm is proposed to obatin a compromise solution of the multi-objective problem. In this algorithm, a number of decision makers are called subsystems, which co-operate with one another in order to attain the goal of the overall system. In our algorithm, all jobs and the set of multi-function machine are defined as the subsystem because their objective functions are competitive. They determine the scheduling plan on the basis of their co-operation and the satisfaction of their own objective function levels. The effectiveness of the algorithm is investigated by examining numerical results.     

CARCINOGENICITY TEST OF QUERCETIN AND KAEMPFEROL IN RATS BY ORAL ADMINISTRATION

Quercetin and kaempferol were tested for carcinogenicity in rats of both sexes. In Experiment I, 0.1% quercetin or control diet was given to Fischer 344 rats for 540 days. In experiment II, 0.04% kaempferol or control diet was given to ACI rats for 540 days. In both experiments, most tumors found in the experimental groups were also found in the corresponding control groups, and there were no statistical differences in the incidences of tumors in the experimental groups and the respective control groups. Quercetin and kaempferol were not shown to be carcinogenic to rats under these conditions.