We demonstrate a series of multitrityl radical compounds where accurate spin-counting by pulsed electron paramagnetic resonance (EPR) can be achieved at X-band (9 GHz) frequencies, even for molecules with very short and flexible linkers. Multiquantum filter experiments, well-known from NMR, were used to count the number of coupled electron spins in these compounds. The six pulse double quantum filter sequence used in EPR for distance determinations in biradicals was used. Precise phase settings to separate higher quantum coherences were achieved by an arbitrary waveform generator. The trityl radicals have narrow spectral width so that homogeneous excitation of all spins by the pulses is possible. The transversal relaxation times of higher quantum coherences of trityl radicals are sufficiently long to allow their detection. Our results on model compounds show the potential of this approach to determine oligomeric states in protein complexes in their native environment using functionalized trityl spin labels.

Fault tree analysis is a widely adopted technique to systematically analyze causes for a given failure of a complex system. Traditionally, a fault tree is constructed top‐down based on knowledge about the structure of the system and the interaction of subsystems. With the increasing system complexity and the accompanying introduction of model‐based development techniques in the industrial process, a substantial amount of this knowledge is laid down in the system models. The main focus of the presented techniques and tools is to automatically exploit this knowledge by extracting a fault tree suitable for FaulTree+ directly from a given design modeled in Statemate. The resulting fault tree is complete wrt. the specified failure, i.e. the analysis considers every possible causal failure combination which is guaranteed by applying model checking techniques. Using an aircraft Flap control system this paper shows how to smoothly integrate the technique into an existing model‐based process.

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