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Die Produktion von Wasserstoff und Folgeprodukten unter Nutzung erneuerbarer Energien gilt als großer Hoffnungsträger für das Erreichen einer Klimaneutralität. Im Rahmen des Leitprojekts H2Mare soll der Betrieb einer Offshore-Plattform für Power-to-X-Produktionsprozesse erforscht und erprobt werden. Im vorliegenden Beitrag wird zunächst das Projektkonzept einer modularen Offshore-Plattform skizziert. Anschließend werden mit dem Digitalen Zwilling und dem System zur optimalen Betriebsführung zwei Forschungsansätze präsentiert, die zur Effizienzsteigerung dieser Produktionsprozesse beitragen sollen.

Recurrent neural networks and exceedingly Long short-term memory (LSTM) have been investigated intensively in recent years due to their ability to model and predict nonlinear time-variant system dynamics. The present paper delivers a comprehensive overview of existing LSTM cell derivatives and network architectures for time series prediction. A categorization in LSTM with optimized cell state representations and LSTM with interacting cell states is proposed. The investigated approaches are evaluated against defined requirements being relevant for an accurate time series prediction. These include short-term and long-term memory behavior, the ability for multimodal and multi-step ahead predictions and the according error propagation. Sequence-to-sequence networks with partially conditioning outperform the other approaches, such as bidirectional or associative networks, and are best suited to fulfill the requirements.

The frequency of changes in production requirements is continuously increasing due to economic volatility, shorter innovation cycles and product life cycles. Therefore, a prediction of all goals of a production system at development time is impossible, which is leading to an increased reconfiguration demand during operation. Currently, there are still some weaknesses concerning the reconfiguration of production systems, which are highlighted in this article. The future of industrial automation will be dominated by Cyber-Physical Production Systems, which offer many promising potentials. Hence, this contribution discusses the Cyber-Physical Production Systems and some of their potentials regarding the reconfiguration issues. Corresponding concepts are required to utilize these theoretical potentials. Therefore, this research provides a basic concept for self-organized reconfiguration management.

The ecological dimension of literature has found proper attention only in the late 20th century, with the rise of ecocriticism as a new direction of literary studies. Ecocriticism emerged from a revalorization of nature writing in the United States and initially understood itself as a countermovement to the linguistic turn in literary and cultural studies. Since the early 21st century, the scope of ecocritical studies has widened to include literary texts and genres across different periods and cultures. Against the background of the global environmental crisis, it has made a strong case for the contribution of literature, art, and the aesthetic to the critique of anthropocentric master narratives as well as to the imaginative exploration of sustainable alternatives to the historically deranged human–nature relationship. Ecocritical scholars have examined the ecological potential of texts in various periods and literary cultures that make up American literature. They have given particular attention to the Indigenous poetic and storytelling modes of Native Americans, the Romantic and transcendentalist movements of the mid-19th century, the aesthetic practices of modernism and postmodernism, the ethnic diversification of American literature since the late 20th century, and, most obviously, contemporary writing that explicitly defines itself as a critical and creative response to the Anthropocene. Thus, an ecological awareness in American literature emerged in different forms and stages that correspond to major periods, styles, and cultures of literary writing. While it is impossible to do justice to all relevant developments, the rich archive of ecological thought and perception in American literature can be productively brought into the transdisciplinary dialogue of the environmental sciences and humanities. The value of literary texts in relation to other forms of environmental knowledge lies not just in the topics they address but in distinctive aesthetic features, such as embodied multiperspectivity, empathetic imagination, reconnection of cultural to natural ecosystems, polysemic openness, and participatory inclusion of the reader in the transformative experience offered by the texts.

The elements and the elemental have emerged as increasingly productive concepts at the intersection of media theory, ecocriticism, and environmental philosophy. The article builds on this scholarship to discuss the potentials of an elemental approach in literary and cultural studies. Against the backdrop of the climate crisis, it outlines the stakes of an elemental aesthetics capable of interrelating modes of sensory, epistemological, and artistic mediation of ecological relations. As a signifier of animated environments, specific material substances, figurative notions of place, and enabling infrastructures, the elements are key for understanding agency as always already compositional, situated, and distributed. Exploring methodologies of elemental analysis with a focus on American literature and culture, the article concludes by illustrating how an aesthetically grounded conceptualization of agency as elemental is particularly useful for addressing the politics of exposure, emplacement, and extraction in the Anthropocene.

Frontiers in Materials 8, 793120 (2022). doi:10.3389/fmats.2021.793120, The local lattice strain evolution during electrochemical hydrogen charging and mechanical loading in 25Cr-7Ni super duplex stainless steel were measured in-situ using synchrotron high-energy x-ray diffraction. Post-mortem electron backscattered diffraction analysis showed that the austenite phase underwent plastic deformation in the near-surface due to hydrogen-enhanced localized plasticity, where the ferrite phase experienced hardening. In bulk regions, the ferrite was the softer phase, and the austenite remained stiff. Digital image correlation of micrographs recorded, in-situ, during mechanical tensile testing revealed intensified plastic strain localization in the austenite phase, which eventually led to crack initiation. The absorption of hydrogen caused strain localization to occur primarily in austenite grains., Published by Frontiers Media, Lausanne

Journal of alloys and compounds 901, 163616 (2022). doi:10.1016/j.jallcom.2022.163616, Nanocrystalline materials are well known for their beneficial mechanical and physical properties. However, it is of utmost importance to stabilize the microstructure at elevated temperatures to broaden the window of application e.g. by pinning grain boundaries through impurities or oxides. CuCo alloys, severe plastically deformed using high-pressure torsion, were used to investigate the evolution of oxides upon annealing. These investigations were performed using electron microscopy, synchrotron high-energy X-ray scattering and atom probe tomography. Monitoring the evolution of oxides by in-situ small angle scattering investigations indicates the growth of primary oxides as well as the formation of another species of oxide at elevated temperatures. Slightly different coarsening can be observed in heat-treated samples, which can be traced back to the influence of different oxide amounts. The initially supersaturated CuCo matrix changes by the decomposition process as well as Co- and Cu-based oxides formation and growth. It has been found that the major number of oxides which are present after annealing, can already be found in the starting materials., Published by Elsevier, Lausanne

The capabilities of a cyber-physical production system are determined by their physical and virtual elements and their interaction. The interaction between virtual and physical entities must be precisely defined, and it is therefore necessary to develop capability models and requirements that enable self-reconfiguration of different elements and their relationships. Furthermore, an ultra-flexible production system requires communication and analysis of huge amounts of data as well as flexible, near-real-time communication between elements. This paper discusses and describes the functional and technical requirements of an ultra-flexible factory and presents an approach to the semantic structuring of elements and capabilities.

Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.

Electro-organic conversions at an active molybdenum anode enable the formation of fused arenes. High chemoselectivity was achieved under anodic conditions, and a reagent-induced selectivity was observed by comparison with results of MoCl5-mediated reactions. Polycyclic arenes like phenanthrenes, triphenylenes, chrysenes, or helicenes were selectively obtained in yields up to 87% and in some cases unusual rearrangements were crucial for the product formation.

Journal of physics / Condensed matter 33, 105901 (2021). doi:10.1088/1361-648X/abcdb0, Diffraction and imaging using x-rays and neutrons are widely utilized in different fields ofengineering, biology, chemistry and/or materials science. The additional information gainedfrom the diffraction signal by x-ray diffraction and computed tomography (XRD-CT) can givethis method a distinct advantage in materials science applications compared to classicaltomography. Its active development over the last decade revealed structural details in anon-destructive way with unprecedented sensitivity. In the current contribution an attempt toadopt the well-established XRD-CT technique for neutron diffraction computed tomography(ND-CT) is reported. A specially designed ‘phantom’, an object displaying adaptable contrastsufficient for both XRD-CT and ND-CT, was used for method validation. The feasibility ofND-CT is demonstrated, and it is also shown that the ND-CT technique is capable to provide anon-destructive view into the interior of the ‘phantom’ delivering structural informationconsistent with a reference XRD-CT experiment., Published by IOP Publ., Bristol

Ensuring high availability despite the growing frequency of changes in production requirements leads to an increased reconfiguration demand in the domain of industrial automation systems, which will be dominated by Cyber-Physical Production Systems (CPPS) in the future. Therefore, a concept, covering a methodology containing four steps, is utilized to answer the research question how to enhance CPPS with a self-organized reconfiguration management. This contribution focuses on the first two steps of this concept: the identification of reconfiguration demand and the generation of alternative configurations. A condensed presentation of the related work reveals that an interface-oriented formalized process description depicts an appropriate conceptual basis. Building upon this, the presented concept contains a capability model of the CPPS and the reasoning to determine a potential reconfiguration demand, as well as a procedure for the generation of alternative configurations. To evaluate the concept, an agent-based implementation is given, which uses an OPC-UA controlled simulated modular production system as a substitute CPPS in discrete manufacturing.

Corrosion science 184, 109390 (2021). doi:10.1016/j.corsci.2021.109390, Synchrotron high-energy XRD measurements and ab-initio DFT calculations were employed to investigate microstructural degradation of copper upon exposure to sulfide-containing anoxic groundwater simulating nu-clear waste repository. After two-month exposure, the high-energy XRD measurements revealed heterogeneous lattice deformation in the microstructure and lattice expansion in near-surface regions. The DFT calculations show that sulfur promotes hydrogen adsorption on copper. Water causes surface reconstruction and promotes hydrogen insertion into the microstructure, occurring via interstitial sites next to vacancies leading to lattice dilation and metal bond weakening. Hydrogen infusion in the presence of sulfur caused lattice degradation, indicating a risk for H-induced cracking., Published by Elsevier Science, Amsterdam [u.a.]

A new ultrahigh-strength structure is created by severe plastic deformation of a martensitic 0.1 wt.-% C steel using high pressure torsion (HPT) at room temperature. Tensile tests reveal an ultimate tensile strength of 2.4 ± 0.1 GPa after an equivalent strain of evM = 7.5 – to our knowledge the highest tensile strength ever reported for a carbon steel with such low carbon content. During HPT, a lamellar microstructure is formed with decreasing lamellar spacing for increasing plastic strain. Micropillar compression tests give crucial insights into the mechanical properties, which are correlated to the deformation behavior of this material. Strong similarities compared to HPT-treated pearlitic steel are found in spite of the large differences concerning both carbon content and phase composition. The possibilities and limits of strength maximization in carbon steels are evaluated and discussed.