Characteristics of the three-dimensional fluorescence spectra of fossil fuels
We have found some fluorescence characteristics of fossil fuels based on the contour maps of the three-dimensional fluorescence spectra of their non-quenching samples. The common fluorescence characteristic is that the main peaks of various fossil fuels are located in the vicinity of excitation/emission wavelength pair 228nm/340nm. The diversity of fluorescence characteristics can be represented with several indexes α,K ,F and R, and these indexes provide measurable parameters for division of fluorescence fingerprints of fossil fuels. The fluorescence fingerprints of fossil fuels can be divided into five models named O, B, Q, P and G that are corresponding to condensate oil, light oil, heavy oil, coal and natural gas, respectively. The technique has a potential application in study of environment pollution on crude oil and geochemical exploration of fossil fuels.
The paper describes a probabilistic approach based on methods of increasing modelling power and different analytical tractability, to analyse safety of turbine digital control system. First, a Fault-Tree (FT) has been built to model the system, assuming independent failures and binary states of its components. To include multi-states and sequentially dependent failures of the system components and to perform diagnoses, FT has been converted into a Bayesian Net. Moreover, to accommodate repair activity, FT has been converted into a Stochastic Petri Net. Due to the very large space of states of the resulting model, a coloured Petri Net model have been built to alleviate the state explosion problem. Safety measures have been computed, referring to the emergent standard IEC 61508. The applicability, the limits and the main selection criteria of the investigated methods are provided.