The present work deals with nitrogen-doped stoichiometric TiO2:N and non-stoichiometric TiO2−x:N thin films deposited by means of dc-pulsed reactive sputtering for application as photoanodes for hydrogen generation from water, using solar energy. Stoichiometric thin films of TiO2 crystallize as a mixture of anatase and rutile while rutile phase predominates in TiO2:N at higher nitrogen flow rates as shown by X-ray diffraction at grazing incidence, XRD GID. Lack of bulk nitridation of stoichiometric TiO2:N is indicated by valence-to-core X-ray emission spectroscopy, XES, analysis. The energy band gap as well as flat band potential remain almost unaffected by increasing nitrogen flow rate in this case. In contrast to that, non-stoichiometric thin films of TiO2‑x:N demonstrate systematic evolution of the structural, morphological, optical and photolectrochemical properties upon increasing level of nitrogen doping. Pronounced changes in the growth pattern of non-stoichiometric TiO2-x:N upon varied nitrogen flow rate, demonstrated by scanning electron microscopy, SEM, can be easily correlated with the crystallographic properties studied by XRD GID. Relative positions of Kβ’’ XES lines of the TiO2-x:N thin films, which depend strongly on the nature of the ligands and their local coordination, change with the increasing nitrogen flow. Doping of nonstoichiometric titanium dioxide with nitrogen shifts the absorption spectrum towards the visible range and increases considerably the flat band potential which is beneficial for water photolysis.
A process is an ordered set of related activities taking place in a given time. Processes are present in all branches of the economy, engineering, science, etc. Due to the huge amount of data produced the rapid development of data mining techniques has been observed. Similar methods are also used in the context of processes and are called process mining. The main task of process mining is to create a process model, which is used to reason about the process and to make decisions inside it. The process model may be used to discuss responsibilities, simulations, predictions, etc. The main data structures in process mining are event logs. It is always very important to have correct data which makes creating a reliable process model possible. In this paper the basic guidelines for recording such event logs have been described and conclusions were drawn. The main focus of this research was transport problems.
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