Event time diagram

The OWR protective systems were modeled with event tree diagrams for the time sequence following an initiating event to fuel damage or safe shutdown. Fault trees were used to find the probability of failure of each protective system in a particular event tree. 

Radiogenic isotopes have proved a most powerful tool for understanding mantle processes. By studying mantle peridotites and mantle-derived melts from a variety of different geological time periods it is possible to define evolutionary curves for the different isotopic systems within the mantle. These curves, when plotted on isotope ratio versus time diagrams, can be used to characterize the chemical evolution of the mantle over time. Deviations from the chondritic trend are used to identify chemical fractionation events in the mantle during Earth history. Of particular... 

FIGURE 3.29 eH time diagrams for the evolution of the Earth s mantle, (a) The mantle evolution curve of Vervoort and Blichert-Toft (1999) showing pre-3.0 Ga fractionation followed by a less extreme fractionation event. The mantle curve indicates that the mantle was depleted in Lu relative to Hf. Negative eHf-values would imply derivation from an enriched source such as enriched mantle or ancient continental crust, (b) A proposed eH -mantle evolution curve based upon eH -values calculated using the fast decay sheme of Bizzarre et al. (2003) - A = 1.983 X 10-11. This dataset supports the mantle evolution curve proposed by Vervoort and Blichert-Toft (1999) shown in (a). The data are taken from Blichert-Toft and Arndt (1999), Vervoort and Blichert-Toft (1999), Amelin et al. (1999), and Amelin et al. (2000). Symbols diamonds, most radiogenic samples Arc, modern arc samples ... 

Figure 4. Two timing diagrams that specify the master read operation on the Intel Multibus. The top diagram is the synchronous arbitration sequence while the bottom diagram is the asynchronous data transaction. The diagrams are linked at the events labeled A, B, and C. The links are used to specify common points in time across the two diagrams so that the sequences of events can be merged. Start (S) and end (E) events for the sequence are also specified. Labels on two of the waveforms (e.g., (NOT Address)) specify the flow of data values across the interfaces. ...

The implications of the unified representation for high-level specification seem to all be beneficial. One of these benefits is that the representation supports synchronous and asynchronous behavior equally well through the use of an asynchronous communicating processes model. Input data becomes available, is operated upon, and output data is made available. The use of specialized description methods for the interface and data-flow behavior is encouraged by the clean separation between the two portions of the graph. For example, an HDL with send and receive constructs can be used to describe the data-flow and timing diagrams can be used to represent the interface details. The interconnections between the two are made between the data event nodes on the interface and the send and receive operation nodes in the data-flow. Of course, the basic block structure of the description must be identical in the two representations. 

Use of structured techniques, such as event trees or event sequence diagrams Identification of significant occurrences on a time-scale, e.g. flux monitor trip and start of insertion of control rods ... 

For severe accidents, reported parameters are similar to those for LWRs, as described in Ref. [13]. The inventory of the moderator and the shield tank water as a function of time should be included, as these sources of water can delay the progression of the accident significantly. An event sequence diagram, with timing, is particularly helpful. 

Batch processes can be synthesized by first synthesizing a continuous process and then converting it to batch operation. A Gantt (time-event) diagram can be used to identify the scope for improved equipment utilization and the need for intermediate storage. 

Gantt charts are limited in their ability to show the interdependencies of activities. In projects where the steps flow in a simple sequence of events, they can portray adequate information for project management. However, when several steps are under way at the same time and a high level of interdependency exists among the various steps, PERT diagrams are a better choice. 

Figure 18. (a) Schematic diagram showing a reactive event A —> B. (b) Plot of the time-... 

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