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Instrumentation and control systems significantly affect the safety and reliability of nuclear power plants. In this study, we analyze the cause of failure of the electronic card constituting the instrumentation and control system as it is the most typical reason for the failure of optocouplers. The lifetime of optocouplers must be predicted accurately to ensure high‐reliability nuclear power plants. While acceleration tests have been performed to predict the lifetime of optocouplers more efficiently, it is preferable to perform accelerated degradation tests rather than accelerated life tests. In this paper, accelerated degradation tests are performed on optocouplers at various temperatures and voltages. To derive the degradation curve model of the optocoupler using the results of accelerated degradation tests, we use the most suitable model from OriginLab. The parameter values of the proposed degradation curve model are calculated by applying the Arrhenius model and Weibull distribution, and the lifetime of the optocoupler is estimated by using the proposed degradation curve model. [ABSTRACT FROM AUTHOR]

This paper proposes an automated scanning process of a structured light system for objects without overhangs. The processes for scanning those objects need to plan scanning directions that minimise the missing area on a three-dimensional surface during the scanning process. Thus, the processes require an approach that finds the next scanning direction efficiently in terms of computational costs. This paper develops a scanning simulation approach to meet this requirement. In order to apply the developed approach, the proposed process generates asolution spacefor candidate-scanning directions, and represents an intermediate 3D model. The developed approach traverses the solution space in a virtual environment and executes virtual scanning for the intermediate 3D model. The virtual scanning result of each candidate-scanning direction is analysed in order to evaluate the contribution for filling missing area. The proposed process defines key scanning directions in the solution space through the iterative execution of the developed approach. The proposed process has been implemented, and applied to the scanning experiments of dental impressions. [ABSTRACT FROM PUBLISHER]

The global number of bees has recently declined. One reason is pathogenic microorganisms including Paenibacillus larvae, which causes American foulbrood disease, and Melissococcus plutonius, which causes European foulbrood disease. The aim of this study was to identify new antimicrobial agents against foulbrood disease. Broth-microdilution assays with 20 natural compounds were used to detect the in vitro antimicrobial activity against foulbrood disease, and MTT assays were performed to determine cytotoxicity against a human cell line. 4-Hydroxydericin, sophoraflavanone G, acetylshikonin, and kurarinone were found to have antimicrobial activity against P. larvae and M. plutonius, with less cytotoxicity against HaCaT cells. In addition, these compounds have a synergic effect with tetracycline or macelignan, which could potentially be effective to control foulbrood disease of honey bees. [ABSTRACT FROM AUTHOR]

The objective of this study is to propose a framework of virtual plant models for the verification of PLC logic through modeling and simulation. The proposed virtual plant model consists of three types of object: the virtual device model (object model), the intermediary transfer model (functional model), and the PLC program & HMI (dynamic model). A virtual device model consists of a physical part, which is used to represent the properties of a real device and a logical part, which is used to manage the device's operation. For the fidelity of the virtual plant model, an intermediary transfer model controls the virtual device through a PLC program and sends information on the virtual device's state to the supervisory control model. Moreover, the PLC program and HMI are used for constructing communication environments similar to a real manufacturing line. For the implementation of the proposed virtual plant model, this study employs an I/O model based on the formalism of Automata and Discrete Event Systems Specifications (DEVS). As a result of the application to a car assembly line, 18 error codes are detected through the manual mode and have been revised. Finally, we can confirm there is no sequential error in the PLC program by checking the time chart. Moreover, the bottleneck and ramp-up/down times are reduced when a manufacturing system/line is built. [ABSTRACT FROM AUTHOR]

In this paper, an approach is proposed that verifies the controller logic processes for the automobile industry via simulation. For this purpose, a state-based object model that creates a virtual car body assembly line is proposed and a verification methodology using observed signal sequences during the simulation is proposed. This approach was applied to an assembly line controlled by a PLC and the effectiveness of the proposed system was explained in a case study. [ABSTRACT FROM AUTHOR]