Reliability Analysis of Safety Grade Programmable Logic Controller
This paper focuses on the random hardware failures necessary for the safety assessment of the reactor protection system (RPS). A prediction method of the hardware failure rate for safety assessment is suggested, and applied to the safety grade programmable logic controller (PLC) to identify design weak points from a safety point of view
A Middleware Layer Monitoring Structure for the Real-time Middleware
This paper proposes MMS (TMO model-based middleware monitoring structure), a structure for monitoring the middleware. MMS can be an infrastructure to check the performance and stability of the middleware, and to guarantee the reliable operation of the TMO applications by managing the operational status of the middleware threads. Moreover, this paper implements a middleware monitor as a supporting tool for developers to monitor the MMS-instrumented middleware. Thus, developer can manage the real-time system more stably, using the MMS-instrumented middleware and the middleware monitor proposed in this paper
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.