Ontologies4Chem: The landscape of ontologies in chemistry

For a long time, databases such as CAS, Reaxys, PubChem or ChemSpider mostly rely on unique numerical identifiers or chemical structure identifiers like InChI, SMILES or others to link data across heterogeneous data sources. The retrospective processing of information and fragmented data from text publications to maintain these databases is a cumbersome process. Ontologies are a holistic approach to semantically describe data, information and knowledge of a domain. They provide terms, relations and logic to semantically annotate and link data building knowledge graphs. The application of standard taxonomies and vocabularies from the very beginning of data generation and along research workflows in electronic lab notebooks (ELNs), software tools, and their final publication in data repositories create FAIR data straightforwardly. Thus a proper semantic description of an investigation and the why, how, where, when, and by whom data was produced in conjunction with the description and representation of research data is a natural outcome in contrast to the retrospective processing of research publications as we know it. In this work we provide an overview of ontologies in chemistry suitable to represent concepts of research and research data. These ontologies are evaluated against several criteria derived from the FAIR data principles and their possible application in the digitisation of research data management workflows

Fracture properties of CrN hard coatings: Influence of the microstructure, alloying elements, and coating architecture

Transition metal nitrides are well known and applied as protective coating materials based on their unique refractory characteristics, such as high hardness or Young’s modulus. However, for long-term applications, the fracture toughness KIC is an essential factor as the integrity of the coating-substrate interface is impaired by cracking and subsequent environmental attacks. Please click Download on the upper right corner to see the full abstract

Mechanical properties and fracture behavior of TiB2+z thin films

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Micro-mechanical testing of transition metal (oxy)nitride coatings

Transition metal (oxy)nitride coatings are used in polymer forming operations for a combination of outstanding wear resistance and chemical compatibility with the polymer materials. Varying the chemical composition and deposition parameters for the coatings will optimise mechanical properties by a combination of chemistry and microstructural optimisation. By developing a representative model for these materials, these materials can be rapidly and efficiently prototyped and improved. However, as both chemistry and microstructure play a role in the material properties, both of these variables must be taken account of in this model. This work demonstrates the first steps in linking quantum-mechanics, micro-mechanics, and meso-scale finite element models together in order to fully understand the behaviour of these coatings. Please click Additional Files below to see the full abstract

Sektionskonzept Meta(daten), Terminologien und Provenienz zur Einrichtung einer Sektion im Verein Nationale Forschungsdateninfrastruktur (NFDI) e.V

Die Sektion befasst sich mit den Themenbereichen (Meta)daten, Terminologien und Provenienz. Aufgabenfelder der Sektion umfassen organisatorische Aspekte (Kollaboration, Wissenstransfer), inhaltliche Aspekte (z.B. Modellierung/Ontologien) und infrastrukturelle Perspektiven (Entwicklung von Standards / Basisdiensten). Eine der wesentlichen Aufgaben der Sektion wird sein, die Arbeit der NFDI-Konsortien im Bereich (Meta)daten, Terminologien und Provenienz entlang der FAIR Kriterien wechselseitig sichtbar zu machen, zu harmonisieren und nachnutzbar zu machen. Hierbei wird die Sektion in enger Rückkopplung mit den Sektionen “Common Infrastructures” sowie “Ethical, Social and Legal Aspects” insbesondere die Themenbereiche Terminologien und Provenienz bearbeiten. (1) Im Themenbereich Metadaten und Forschungsdaten - im Folgenden kurz (Meta)daten - beschäftigt sich die Sektion mit Fragen zur (Meta-)daten-Harmonisierung, Auffindbarkeit von Daten, allgemeine Daten- und Metadaten-Standards mit Blick auf ein mögliches NFDI-Kernmetadatenformat sowie Formatumwandlungen und Persistent-Identifier-Systemen. (2) Im Themenbereich Terminologien beschäftigt sich die Sektion mit community- und disziplinenübergreifenden Definitionen von Top-Level Ontologien und Mappings von Ontologien sowie Best Practices zur Modellierung von Terminologien, Vokabularen und Ontologien sowie darauf aufbauenden Diensten zur Datenintegration (z.B. Terminology Service, Knowledge Graphs etc.). (3) Im Themenbereich Provenienz befasst sich die Sektion mit rechtlichen, technischen und kulturellen Aspekten des Entstehungskontextes von (Meta)daten (z.B. im Rahmen von Experimenten, Laborbüchern, Digitalisierungsprozessen etc.) und entwirft Vorschläge für einheitliche und nachvollziehbare Dokumentationsverfahren zur Beantwortung der Fragen nach dem was, wo, wann, wer, wie und warum der Datenerzeugung und Datenprozessierung. Hierbei entwickelt die Sektion Empfehlungen für die Abbildung der Provenienz in einem möglichen NFDI-Kernmetadatenformat

Synthesis, electronic structure, elastic properties, and interfacial behavior of icosahedral boron-rich solids

Boron-rich solids are commonly characterized by icosahedral clusters, where 12 B atoms form an icosahedron, giving rise to outstanding mechanical and transport properties. However, broader applications are limited due to the high synthesis temperature required to obtain the icosahedra-based crystalline structure. Utilizing high power pulsed magnetron sputtering (HPPMS), the deposition temperature may be lowered as compared to direct current magnetron sputtering by enhanced surface diffusion. Therefore, HPPMS was utilized to investigate the influence of the substrate temperature on the structural evolution of B-rich Al-Y-B thin films. The formation of the intended AlYB$_{14}$ phase together with the (Y,Al)B$_{6}$ impurity phase, containing 1.8 at.% less B than AlYB$_{14}$, was observed at a growth temperature of 800 °C and hence 600 °C below the bulk synthesis temperature. Based on density functional theory (DFT) calculations it is inferred that minute compositional variations may lead to formation of competing phases, such as (Y,Al)B$_{6}$. Furthermore, 800 °C still limits the usage significantly. Therefore, quantum mechanical material design was applied to identify phases with even higher phase stabilities compared to AlYB$_{14}$. Phase stability of T$_{0.75}$Y$_{0.75}$B$_{14}$ (T = Sc, Ti, V, Y, Zr, Nb, Si) critically depends on the exact magnitude of charge transferred by T and Y to the B icosahedra. The highest phase stabilities have been identified for Sc$_{0.75}$Y$_{0.75}$B$_{14}$, Ti$_{0.75}$Y$_{0.75}$B$_{14}$, and Zr$_{0.75}$Y$_{0.75}$B$_{14}$. In combination with Young’s modulus values up to 517 GPa these phases are very interesting from a wear-resistance point of view. Still high synthesis temperatures limit the use of such systems onto technologically relevant substrate materials. However, amorphous B-rich solids, which can be synthesized without additional heating, exhibit attractive mechanical and electrical properties. Within these solids a dense B network, characterized by icosahedra-like bonding, provides the required electronic structure. Young’s modulus values of amorphous T’$_{0.75}$Y$_{0.75}$B$_{14}$ (a-T’$_{0.75}$Y$_{0.75}$B$_{14}$, T’ = Sc, Ti, V, Y, Zr, Nb) reach up to 393 GPa for a-Nb$_{0.75}$Y$_{0.75}$B$_{14}$. To critically appraise these predicted data experimentally, a-TiYB$_{14}$ and a-ZrYB$_{14}$ thin films were synthesized. Chemical composition analysis revealed the presence of high oxygen impurities. The measured Young’s modulus values for a-TiYB$_{14}$ (301±8 GPa) and a-ZrYB$_{14}$ (306±9 GPa) were more than 20% smaller than the predicted ones but still comparable to other hard coatings. These deviations can be rationalized based on theoretical data revealing that the presence of oxygen impurities disrupts the dense B network causing a concomitant decrease in molar density and Young’s modulus. This in turn highlights the possible usage of amorphous transition metal borides, which can even be synthesized at room temperature, exhibiting stiffness values of up to 82% compared to TiB$_{2}$. Therefore, as a first step towards applications, the suitability of a-AlYB$_{14}$ as a coating for polymer forming was investigated. The influence of surface oxidation on the interaction between CH$_{4}$ and a-AlYB$_{14}$ has been studied theoretically by using DFT and experimentally by ultra-high vacuum atomic force microscopy. Theory and experiments show the same trend as interaction increases for the oxidized scenario. Oxygen chemisorption induces changes in surface bonding leading to the higher interaction for the latter case. The data serve as proof of concept for the here implemented research strategy for exploring polymer hard coating interactions in varying atmospheres based on correlative experimental and theoretical methods.The results of this work contribute to the understanding of the electronic structure-elasticity relationship of icosahedral B-rich solids as well as comprise important aspects for applications, such as the influence of impurity incorporations on the elastic properties, the formation of competing phases during synthesis, and the effect of atmosphere exposure on the interaction with a workpiece