Unknown logic state

Logically it follows that a traceability chain can equally be stated to the value of a reference measurement obtained by a reference measurement producer on the analyst s sample at point 1 in Fig. 1. This concept has the unknown sample travelling from the analyst to the (reference measurement) producer, rather than having the (reference) material travelling from the (reference material) producer to the analyst. This approach will be developed further on another occasion.)... 

But when radioactivity was discovered thorium and uranium, that is the heaviest elements in the Mendeleev table, were found to possess this property. It would logically seem that the transuranium elements had existed in nature in past but, being highly unstable, had decayed to other, known elements. This simple explanation had a hidden trap, namely, the possible half-lives of even the nearest right-hand neighbours of uranium were quite unknown. Nobody could state with certainty that these hypothetical elements were less stable than uranium and thorium. Thus, it would be reasonable to look for natural transuranium elements. 

The difficulty of the experimental proof of the LLCP hypothesis, apart from the crystallization in NML, was that the amorphous ices were solid and not in the thermodynamical equilibrium. As for liquid, it was in the equilibrium and could be a sole state once pressure and temperature were fixed. Therefore, it would be possible to prove the discontinuity of the transition between two different liquids. However, regarding liquid water, LDL and HDL would crystallize immediately in NML, and we could not observe the LLT directly. In contrast, although we could observe the LDA HDA transition, the nonequilibrium nature of LDA and HDA threw doubt on the discontinuity of the transition logically. That is, the existence of the barrier in Fig. 5b was doubted the potential surface between LDA and HDA might be flat by nature. Then, the apparently discontinuous LDA-to-HDA transition (Fig. 7) might be, correctly, continuous or caused by unknown sticky relaxation of a nonequUibrium LDA state. If so, LLT of water would be continuous and LLCP would not exist. 

The alternative way to deal with unknown or other such states is to catch the good ones and throw out the bad. This approach should be used wiffi more caution as not all synthesis tools support the required constructs. The advantage of this method is that the VHDL can be constructed so that the simulation will accurately reflect the operation of the synthesized circuit design. Wiih the previous method, tfds would only occur after the initialization signal had been issued. This topic is discussed in more detail in Chapter 8 when multivalued logic systems are introduced. 

Although the logic of this statement is correct, it by no means covers all possible states that can occur during simulation. These include uninitialized, unknown or weak low to name but a few. 

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