TY - JOUR A1 - Kotz, Maximilian A1 - Levermann, Anders A1 - Wenz, Leonie T1 - The effect of rainfall changes on economic production JF - Nature : the international journal of science N2 - Macro-economic assessments of climate impacts lack an analysis of the distribution of daily rainfall, which can resolve both complex societal impact channels and anthropogenically forced changes(1-6). Here, using a global panel of subnational economic output for 1,554 regions worldwide over the past 40 years, we show that economic growth rates are reduced by increases in the number of wet days and in extreme daily rainfall, in addition to responding nonlinearly to the total annual and to the standardized monthly deviations of rainfall. Furthermore, high-income nations and the services and manufacturing sectors are most strongly hindered by both measures of daily rainfall, complementing previous work that emphasized the beneficial effects of additional total annual rainfall in low-income, agriculturally dependent economies(4,7). By assessing the distribution of rainfall at multiple timescales and the effects on different sectors, we uncover channels through which climatic conditions can affect the economy. These results suggest that anthropogenic intensification of daily rainfall extremes(8-10) will have negative global economic consequences that require further assessment by those who wish to evaluate the costs of anthropogenic climate change. Y1 - 2022 U6 - https://doi.org/10.1038/s41586-021-04283-8 SN - 0028-0836 SN - 1476-4687 VL - 601 IS - 7892 SP - 223 EP - 227 PB - Macmillan Publishers Limited, part of Springer Nature CY - London ER - TY - JOUR A1 - Kramer, Koen A1 - Bouriaud, Laura A1 - Feindt, Peter H. A1 - van Wassenaer, Lan A1 - Glanemann, Nicole A1 - Hanewinkel, Marc A1 - van der Heide, Martijn A1 - Hengeveld, Geerten M. A1 - Hoogstra, Marjanke A1 - Ingram, Verina A1 - Levermann, Anders A1 - Lindner, Marcus A1 - Mátyás, Csaba A1 - Mohren, Frits A1 - Muys, Bart A1 - Nabuurs, Gert-Jan A1 - Palahi, Marc A1 - Polman, Nico A1 - Reyer, Christopher P. O. A1 - Schulze, Ernst-Detlef A1 - Seidl, Rupert A1 - de Vries, Wim A1 - Werners, Saskia E. A1 - Winkel, Georg A1 - Yousefpour, Rasoul T1 - Perspective Roadmap to develop a stress test for forest ecosystem services supply JF - One Earth N2 - Forests play a key role in a bio-based economy by providing renewable materials, mitigating climate change, and accommodating biodiversity. However, forests experience massive increases in stresses in their ecological and socioeconomic environments, threatening forest ecosystem services supply. Alleviating those stresses is hampered by conflicting and disconnected governance arrangements, competing interests and claims, and rapid changes in technology and social demands. Identifying which stresses threaten forest ecosystem services supply and which factors hamper their alleviation requires stakeholders' perceptions. Stakeholder-oriented stress tests for the supply of forest ecosystem services are therefore necessary but are not yet available. This perspective presents a roadmap to develop a stress test tailored to multiple stakeholders' needs and demands across spatial scales. We provide the Cascade and Resilience Rosetta, with accompanying performance- and resilience indicators, as tools to facilitate development of the stress test. The application of the stress test will facilitate the transition toward a bio-based economy in which healthy and diverse forests provide sustainable and resilient ecosystem services. Y1 - 2022 U6 - https://doi.org/10.1016/j.oneear.2021.12.009 SN - 2590-3330 SN - 2590-3322 VL - 5 IS - 1 SP - 25 EP - 34 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Kranjc Horvat, Anja T1 - Particle physics in high-school education T1 - Teilchenphysik im Oberstufenunterricht BT - what should students and teachers learn? BT - was sollten Jugendliche und Lehrpersonen lernen? N2 - Elementary particle physics is a contemporary topic in science that is slowly being integrated into high-school education. These new implementations are challenging teachers’ professional knowledge worldwide. Therefore, physics education research is faced with two important questions, namely, how can particle physics be integrated in high-school physics curricula and how best to support teachers in enhancing their professional knowledge on particle physics. This doctoral research project set up to provide better guidelines for answering these two questions by conducting three studies on high-school particle physics education. First, an expert concept mapping study was conducted to elicit experts’ expectations on what high-school students should learn about particle physics. Overall, 13 experts in particle physics, computing, and physics education participated in 9 concept mapping rounds. The broad knowledge base of the experts ensured that the final expert concept map covers all major particle physics aspects. Specifically, the final expert concept map includes 180 concepts and examples, connected with 266 links and crosslinks. Among them are also several links to students’ prior knowledge in topics such as mechanics and thermodynamics. The high interconnectedness of the concepts shows possible opportunities for including particle physics as a context for other curricular topics. As such, the resulting expert concept map is showcased as a well-suited tool for teachers to scaffold their instructional practice. Second, a review of 27 high-school physics curricula was conducted. The review uncovered which concepts related to particle physics can be identified in most curricula. Each curriculum was reviewed by two reviewers that followed a codebook with 60 concepts related to particle physics. The analysis showed that most curricula mention cosmology, elementary particles, and charges, all of which are considered theoretical particle physics concepts. None of the experimental particle physics concepts appeared in more than half of the reviewed curricula. Additional analysis was done on two curricular subsets, namely curricula with and curricula without an explicit particle physics chapter. Curricula with an explicit particle physics chapter mention several additional explicit particle physics concepts, namely the Standard Model of particle physics, fundamental interactions, antimatter research, and particle accelerators. The latter is an example of experimental particle physics concepts. Additionally, the analysis revealed that, overall, most curricula include Nature of Science and history of physics, albeit both are typically used as context or as a tool for teaching, respectively. Third, a Delphi study was conducted to investigate stakeholders’ expectations regarding what teachers should learn in particle physics professional development programmes. Over 100 stakeholders from 41 countries represented four stakeholder groups, namely physics education researchers, research scientists, government representatives, and high-school teachers. The study resulted in a ranked list of the 13 most important topics to be included in particle physics professional development programmes. The highest-ranked topics are cosmology, the Standard Model, and real-life applications of particle physics. All stakeholder groups agreed on the overall ranking of the topics. While the highest-ranked topics are again more theoretical, stakeholders also expect teachers to learn about experimental particle physics topics, which are ranked as medium importance topics. The three studies addressed two research aims of this doctoral project. The first research aim was to explore to what extent particle physics is featured in high-school physics curricula. The comparison of the outcomes of the curricular review and the expert concept map showed that curricula cover significantly less than what experts expect high-school students to learn about particle physics. For example, most curricula do not include concepts that could be classified as experimental particle physics. However, the strong connections between the different concept show that experimental particle physics can be used as context for theoretical particle physics concepts, Nature of Science, and other curricular topics. In doing so, particle physics can be introduced in classrooms even though it is not (yet) explicitly mentioned in the respective curriculum. The second research aim was to identify which aspects of content knowledge teachers are expected to learn about particle physics. The comparison of the Delphi study results to the outcomes of the curricular review and the expert concept map showed that stakeholders generally expect teachers to enhance their school knowledge as defined by the curricula. Furthermore, teachers are also expected to enhance their deeper school knowledge by learning how to connect concepts from their school knowledge to other concepts in particle physics and beyond. As such, professional development programmes that focus on enhancing teachers’ school knowledge and deeper school knowledge best support teachers in building relevant context in their instruction. Overall, this doctoral research project reviewed the current state of high-school particle physics education and provided guidelines for future enhancements of the particle physics content in high-school student and teacher education. The outcomes of the project support further implementations of particle physics in high-school education both as explicit content and as context for other curricular topics. Furthermore, the mixed-methods approach and the outcomes of this research project lead to several implications for professional development programmes and science education research, that are discussed in the final chapters of this dissertation. N2 - Elementarteilchenphysik ist ein aktuelles naturwissenschaftliches Thema, das langsam in den Oberstufenunterricht integriert wird. Diese neuen Umsetzungen stellen das Professionswissen der Lehrpersonen weltweit infrage. Die Fachdidaktik sieht sich daher mit zwei wichtigen Fragen beschäftigt: Wie kann die Teilchenphysik in die Oberstufenlehrpläne integriert werden und wie können Lehrpersonen am besten dabei unterstützt werden, ihr Professionswissen über Teilchenphysik zu erweitern? Im Rahmen dieses Promotionsprojekts wurden drei Studien zum Unterricht von Teilchenphysik in der Oberstufe durchgeführt, um bessere Leitlinien für die Beantwortung dieser beiden Fragen zu erarbeiten. Zunächst wurde eine Concept-Mapping-Studie durchgeführt, um die Erwartungen von ExpertInnen darüber zu ermitteln, was SchülerInnen der Oberstufe über Teilchenphysik lernen sollten. Insgesamt nahmen 13 ExpertInnen aus den Bereichen Teilchenphysik, Informatik und Physikdidaktik an 9 Concept-Mapping-Runden teil. Die breite Wissensbasis der Experten stellte sicher, dass die endgültige Expert Concept Map alle wichtigen Aspekte der Teilchenphysik umspannt. Die endgültige Expert Concept Map enthält 180 Konzepte und Beispiele, die mit 266 Verbindungen und Querverweisen verknüpft sind. Darunter befinden sich auch mehrere Bezüge zum Vorwissen der SchülerInnen in Themen wie Mechanik und Thermodynamik. Die starke Vernetzung der Konzepte zeigt, dass es möglich ist, die Teilchenphysik als Kontext für andere Lehrplanthemen zu nutzen. Die so entstandene Expert Concept Map wird als geeignetes Instrument für Lehrpersonen zur Unterstützung ihrer Unterrichtspraxis vorgestellt. Zweitens wurde ein Vergleich von 27 Physiklehrplänen für die Oberstufe durchgeführt. Dabei wurde festgestellt, welche Konzepte mit Bezug zur Teilchenphysik in den meisten Lehrplänen zu finden sind. Jeder Lehrplan wurde von zwei Gutachtern mittels einer Kodieranleitung mit 60 Konzepten zur Teilchenphysik analysiert. Die Lehrplananalyse ergab, dass in den meisten Lehrplänen Kosmologie, Elementarteilchen und Ladungen erwähnt werden, die alle als theoretische Konzepte der Teilchenphysik gelten. Keines der Konzepte der experimentellen Teilchenphysik kam in mehr als der Hälfte der untersuchten Lehrpläne vor. Eine zusätzliche Analyse wurde für zwei Untergruppen von Lehrplänen durchgeführt, nämlich Lehrpläne mit und Lehrpläne ohne ein explizites Teilchenphysik-Kapitel. In Lehrplänen mit einem expliziten Teilchenphysik-Kapitel werden mehrere zusätzliche Teilchenphysik-Konzepte erwähnt, nämlich das Standardmodell der Teilchenphysik, fundamentale Wechselwirkungen, Antimaterieforschung und Teilchenbeschleuniger. Letzteres ist ein Beispiel für Konzepte der experimentellen Teilchenphysik. Darüber hinaus ergab die Analyse, dass die meisten Lehrpläne Aspekte der Nature of Science und der Geschichte der Physik enthalten, obwohl beide typischerweise als Kontext bzw. als Hilfsmittel für den Unterricht verwendet werden. Drittens wurde eine Delphi-Studie durchgeführt, um die Erwartungen von Stakeholder in Bezug darauf zu untersuchen, was Lehrpersonen in Weiterbildungsprogrammen zur Teilchenphysik lernen sollten. Über 100 Stakeholder aus 41 Ländern vertraten vier Stakeholder-Gruppen, nämlich FachdidaktikerInnen, FachwissenschaftlerInnen, RegierungsvertreterInnen und Lehrpersonen. Das Ergebnis der Studie ist eine Rangliste der 13 wichtigsten Themen, die in Fortbildungsprogrammen für Teilchenphysik behandelt werden sollten. Die am höchsten bewerteten Themen waren Kosmologie, das Standardmodell der Teilchenphysik und Anwendungen der Teilchenphysik. Alle Stakeholder-Gruppen waren sich über die Gesamtwertung der Themen einig. Während die am höchsten bewerteten Themen wiederum eher theoretischer Natur waren, erwarten die Stakeholder auch, dass Lehrpersonen etwas über experimentelle Teilchenphysik Themen lernen, die mit mittlerer Bedeutung eingestuft wurden. Mit den drei Studien wurden zwei Forschungsziele dieses Promotionsprojekts verfolgt. Das erste Forschungsziel bestand darin, zu untersuchen, inwiefern die Teilchenphysik in den Physiklehrplänen für die Oberstufe behandelt wird. Der Vergleich der Ergebnisse der Lehrplananalyse und der Expert Concept Map zeigte, dass die Lehrpläne deutlich weniger abdecken als das, was ExpertInnen von OberstufenschülerInnen über Teilchenphysik erwarten. Beispielsweise enthalten die meisten Lehrpläne keine Konzepte, die der experimentellen Teilchenphysik zugeordnet werden können. Die vielfältigen Verbindungen zwischen den verschiedenen Konzepten zeigen jedoch, dass die experimentelle Teilchenphysik als Kontext für Konzepte der theoretischen Teilchenphysik, Nature of Science und andere Lehrplanthemen verwendet werden kann. Auf diese Weise kann die Teilchenphysik im Unterricht eingeführt werden, selbst wenn diese (noch) nicht explizit im jeweiligen Lehrplan erwähnt wird. Das zweite Forschungsziel bestand darin, herauszufinden, welche Aspekte des Fachwissens Lehrpersonen über Teilchenphysik vermittelt werden sollen. Der Vergleich der Ergebnisse der Delphi-Studie mit den Resultaten der Lehrplananalyse und der Expert Concept Map zeigte, dass die Stakeholder im Allgemeinen erwarten, dass Lehrpersonen ihr Schulwissen im Sinne der Lehrpläne erweitern. Darüber hinaus wird von den Lehrpersonen erwartet, dass sie ihr Schulwissen vertiefen, indem sie lernen, wie sie Konzepte aus ihrem Schulwissen mit anderen Konzepten der Teilchenphysik verbinden können. Fortbildungsprogramme, die den Schwerpunkt auf die Verbesserung des Schulwissens und des vertieften Schulwissens der Lehrpersonen legen, unterstützen somit bestmöglich die Lehrpersonen beim Aufbau relevanter Zusammenhänge für ihren Unterricht. Insgesamt wurde im Rahmen dieses Promotionsprojekts der aktuelle Stand des Teilchenphysikunterrichts in der Oberstufe untersucht und es wurden Leitlinien für die künftige Aufwertung teilchenphysikalischer Inhalte in der Ausbildung von Jugendlichen und Lehrpersonen erarbeitet. Die Ergebnisse des Projekts unterstützen die aktuelle Einführung der Teilchenphysik im Oberstufenunterricht sowohl als expliziten Inhalt als auch als Kontext für andere Lehrplanthemen. Darüber hinaus ergeben sich aus der Methodik und den Ergebnissen dieses Forschungsprojekts mehrere Implikationen für Weiterbildungsprogramme und für die Physikdidaktik, die in den letzten Kapiteln dieser Dissertation diskutiert werden. KW - physics education KW - particle physics KW - high-school education KW - teacher professional development KW - Physik Lehramt KW - Teilchenphysik KW - Lehrerfortbildung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-560260 ER - TY - JOUR A1 - Kranjc Horvat, Anja A1 - Wiener, Jeff A1 - Schmeling, Sascha A1 - Borowski, Andreas T1 - Learning goals of professional development programs at science research institutions BT - a Delphi study with different stakeholder groups JF - Journal of science teacher education : the official journal of the Association for the Education of Teachers in Science N2 - Effective professional development programs (PDPs) rely on well-defined goals. However, recent studies on PDPs have not explored the goals from a multi-stakeholder perspective. This study identifies the most important learning goals of PDPs at science research institutions as perceived by four groups of stakeholders, namely teachers, education researchers, government representatives, and research scientists. Altogether, over 100 stakeholders from 42 countries involved in PDPs at science research institutions in Europe and North America participated in a three-round Delphi study. In the first round, the stakeholders provided their opinions on what they thought the learning goals of PDPs should be through an open-ended questionnaire. In the second and third rounds, the stakeholders assessed the importance of the learning goals that emerged from the first round by rating and ranking them, respectively. The outcome of the study is a hierarchical list of the ten most important learning goals of PDPs at particle physics laboratories. The stakeholders identified enhancing teachers' knowledge of scientific concepts and models and enhancing their knowledge of the curricula as the most important learning goals. Furthermore, the results show strong agreement between all the stakeholder groups regarding the defined learning goals. Indeed, all groups ranked the learning goals by their perceived importance almost identically. These outcomes could help policymakers establish more specific policies for PDPs. Additionally, they provide PDP practitioners at science research institutions with a solid base for future research and planning endeavors. KW - Teacher professional development KW - Delphi study KW - multi-stakeholder KW - analysis KW - pedagogical content knowledge Y1 - 2021 U6 - https://doi.org/10.1080/1046560X.2021.1905330 SN - 1046-560X SN - 1573-1847 VL - 33 IS - 1 SP - 32 EP - 54 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Kretzschmar, Mirjam E. A1 - Ashby, Ben A1 - Fearon, Elizabeth A1 - Overton, Christopher E. A1 - Panovska-Griffiths, Jasmina A1 - Pellis, Lorenzo A1 - Quaife, Matthew A1 - Rozhnova, Ganna A1 - Scarabel, Francesca A1 - Stage, Helena B. A1 - Swallow, Ben A1 - Thompson, Robin N. A1 - Tildesley, Michael J. A1 - Villela, Daniel Campos T1 - Challenges for modelling interventions for future pandemics JF - Epidemics N2 - Mathematical modelling and statistical inference provide a framework to evaluate different non-pharmaceutical and pharmaceutical interventions for the control of epidemics that has been widely used during the COVID-19 pandemic. In this paper, lessons learned from this and previous epidemics are used to highlight the challenges for future pandemic control. We consider the availability and use of data, as well as the need for correct parameterisation and calibration for different model frameworks. We discuss challenges that arise in describing and distinguishing between different interventions, within different modelling structures, and allowing both within and between host dynamics. We also highlight challenges in modelling the health economic and political aspects of interventions. Given the diversity of these challenges, a broad variety of interdisciplinary expertise is needed to address them, combining mathematical knowledge with biological and social insights, and including health economics and communication skills. Addressing these challenges for the future requires strong cross disciplinary collaboration together with close communication between scientists and policy makers. KW - Mathematical models KW - Pandemics KW - Pharmaceutical interventions KW - Non-pharmaceutical interventions KW - Policy support Y1 - 2022 U6 - https://doi.org/10.1016/j.epidem.2022.100546 SN - 1755-4365 SN - 1878-0067 VL - 38 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kroh, Daniel A1 - Eller, Fabian A1 - Schötz, Konstantin A1 - Wedler, Stefan A1 - Perdigón-Toro, Lorena A1 - Freychet, Guillaume A1 - Wei, Qingya A1 - Dörr, Maximilian A1 - Jones, David A1 - Zou, Yingping A1 - Herzig, Eva M. A1 - Neher, Dieter A1 - Köhler, Anna T1 - Identifying the signatures of intermolecular interactions in blends of PM6 with Y6 and N4 using absorption spectroscopy JF - Advanced functional materials N2 - In organic solar cells, the resulting device efficiency depends strongly on the local morphology and intermolecular interactions of the blend film. Optical spectroscopy was used to identify the spectral signatures of interacting chromophores in blend films of the donor polymer PM6 with two state-of-the-art nonfullerene acceptors, Y6 and N4, which differ merely in the branching point of the side chain. From temperature-dependent absorption and luminescence spectroscopy in solution, it is inferred that both acceptor materials form two types of aggregates that differ in their interaction energy. Y6 forms an aggregate with a predominant J-type character in solution, while for N4 molecules the interaction is predominantly in a H-like manner in solution and freshly spin-cast film, yet the molecules reorient with respect to each other with time or thermal annealing to adopt a more J-type interaction. The different aggregation behavior of the acceptor materials is also reflected in the blend films and accounts for the different solar cell efficiencies reported with the two blends. KW - charge-transfer states KW - Frank-Condon analysis KW - morphology KW - organic solar cells Y1 - 2022 U6 - https://doi.org/10.1002/adfm.202205711 SN - 1616-301X SN - 1616-3028 VL - 32 IS - 44 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kruse, Marlen A1 - Altattan, Basma A1 - Laux, Eva-Maria A1 - Grasse, Nico A1 - Heinig, Lars A1 - Möser, Christin A1 - Smith, David M. A1 - Hölzel, Ralph T1 - Characterization of binding interactions of SARS-CoV-2 spike protein and DNA-peptide nanostructures JF - Scientific reports N2 - Binding interactions of the spike proteins of the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) to a peptide fragment derived from the human angiotensin converting enzyme 2 (hACE2) receptor are investigated. The peptide is employed as capture moiety in enzyme linked immunosorbent assays (ELISA) and quantitative binding interaction measurements that are based on fluorescence proximity sensing (switchSENSE). In both techniques, the peptide is presented on an oligovalent DNA nanostructure, in order to assess the impact of mono- versus trivalent binding modes. As the analyte, the spike protein and several of its subunits are tested as well as inactivated SARS-CoV-2 and pseudo viruses. While binding of the peptide to the full-length spike protein can be observed, the subunits RBD and S1 do not exhibit binding in the employed concentrations. Variations of the amino acid sequence of the recombinant full-length spike proteins furthermore influence binding behavior. The peptide was coupled to DNA nanostructures that form a geometric complement to the trimeric structure of the spike protein binding sites. An increase in binding strength for trimeric peptide presentation compared to single peptide presentation could be generally observed in ELISA and was quantified in switchSENSE measurements. Binding to inactivated wild type viruses could be shown as well as qualitatively different binding behavior of the Alpha and Beta variants compared to the wild type virus strain in pseudo virus models. Y1 - 2022 U6 - https://doi.org/10.1038/s41598-022-16914-9 SN - 2045-2322 VL - 12 IS - 1 PB - Macmillan Publishers Limited, part of Springer Nature CY - London ER - TY - JOUR A1 - Krämer, Hauke Kai A1 - Gelbrecht, Maximilian A1 - Pavithran, Induja A1 - Sujith, Ravindran A1 - Marwan, Norbert T1 - Optimal state space reconstruction via Monte Carlo decision tree search JF - Nonlinear Dynamics N2 - A novel idea for an optimal time delay state space reconstruction from uni- and multivariate time series is presented. The entire embedding process is considered as a game, in which each move corresponds to an embedding cycle and is subject to an evaluation through an objective function. This way the embedding procedure can be modeled as a tree, in which each leaf holds a specific value of the objective function. By using a Monte Carlo ansatz, the proposed algorithm populates the tree with many leafs by computing different possible embedding paths and the final embedding is chosen as that particular path, which ends at the leaf with the lowest achieved value of the objective function. The method aims to prevent getting stuck in a local minimum of the objective function and can be used in a modular way, enabling practitioners to choose a statistic for possible delays in each embedding cycle as well as a suitable objective function themselves. The proposed method guarantees the optimization of the chosen objective function over the parameter space of the delay embedding as long as the tree is sampled sufficiently. As a proof of concept, we demonstrate the superiority of the proposed method over the classical time delay embedding methods using a variety of application examples. We compare recurrence plot-based statistics inferred from reconstructions of a Lorenz-96 system and highlight an improved forecast accuracy for map-like model data as well as for palaeoclimate isotope time series. Finally, we utilize state space reconstruction for the detection of causality and its strength between observables of a gas turbine type thermoacoustic combustor. KW - State space reconstruction KW - Embedding KW - Optimization KW - Time series analysis KW - Causality KW - Prediction KW - Recurrence analysis Y1 - 2022 U6 - https://doi.org/10.1007/s11071-022-07280-2 SN - 0924-090X SN - 1573-269X VL - 108 IS - 2 SP - 1525 EP - 1545 PB - Springer CY - Dordrecht ER - TY - THES A1 - Kuhla, Kilian T1 - Impact, distribution, and adaptation T1 - Auswirkung, Verteilung und Anpassung BT - how weather extremes threaten the economic network BT - wie Wetterextreme das ökonomische Netzwerk bedrohen N2 - Weather extremes pose a persistent threat to society on multiple layers. Besides an average of ~37,000 deaths per year, climate-related disasters cause destroyed properties and impaired economic activities, eroding people's livelihoods and prosperity. While global temperature rises – caused by anthropogenic greenhouse gas emissions – the direct impacts of climatic extreme events increase and will further intensify without proper adaptation measures. Additionally, weather extremes do not only have local direct effects. Resulting economic repercussions can propagate either upstream or downstream along trade chains causing indirect effects. One approach to analyze these indirect effects within the complex global supply network is the agent-based model Acclimate. Using and extending this loss-propagation model, I focus in this thesis on three aspects of the relation between weather extremes and economic repercussions. First, extreme weather events cause direct impacts on local economic performance. I compute daily local direct output loss time series of heat stress, river floods, tropical cyclones, and their consecutive occurrence using (near-future) climate projection ensembles. These regional impacts are estimated based on physical drivers and local productivity distribution. Direct effects of the aforementioned disaster categories are widely heterogeneous concerning regional and temporal distribution. As well, their intensity changes differently under future warming. Focusing on the hurricane-impacted capital, I find that long-term growth losses increase with higher heterogeneity of a shock ensemble. Second, repercussions are sectorally and regionally distributed via economic ripples within the trading network, causing higher-order effects. I use Acclimate to identify three phases of those economic ripples. Furthermore, I compute indirect impacts and analyze overall regional and global production and consumption changes. Regarding heat stress, global consumer losses double while direct output losses increase by a factor 1.5 between 2000 – 2039. In my research I identify the effect of economic ripple resonance and introduce it to climate impact research. This effect occurs if economic ripples of consecutive disasters overlap, which increases economic responses such as an enhancement of consumption losses. These loss enhancements can even be more amplified with increasing direct output losses, e.g. caused by climate crises. Transport disruptions can cause economic repercussions as well. For this, I extend the model Acclimate with a geographical transportation route and expand the decision horizon of economic agents. Using this, I show that policy-induced sudden trade restrictions (e.g. a no-deal Brexit) can significantly reduce the longer-term economic prosperity of affected regions. Analyses of transportation disruptions in typhoon seasons indicate that severely affected regions must reduce production as demand falls during a storm. Substituting suppliers may compensate for fluctuations at the beginning of the storm, which fails for prolonged disruptions. Third, possible coping mechanisms and adaptation strategies arise from direct and indirect economic responses to weather extremes. Analyzing annual trade changes due to typhoon-induced transport disruptions depict that overall exports rise. This trade resilience increases with higher network node diversification. Further, my research shows that a basic insurance scheme may diminish hurricane-induced long-term growth losses due to faster reconstruction in disasters aftermaths. I find that insurance coverage could be an economically reasonable coping scheme towards higher losses caused by the climate crisis. Indirect effects within the global economic network from weather extremes indicate further adaptation possibilities. For one, diversifying linkages reduce the hazard of sharp price increases. Next to this, close economic interconnections with regions that do not share the same extreme weather season can be economically beneficial in the medium run. Furthermore, economic ripple resonance effects should be considered while computing costs. Overall, an increase in local adaptation measures reduces economic ripples within the trade network and possible losses elsewhere. In conclusion, adaptation measures are necessary and potential present, but it seems rather not possible to avoid all direct or indirect losses. As I show in this thesis, dynamical modeling gives valuable insights into how direct and indirect economic impacts arise from different categories of weather extremes. Further, it highlights the importance of resolving individual extremes and reflecting amplifying effects caused by incomplete recovery or consecutive disasters. N2 - Wetterextreme stellen für die Gesellschaft eine anhaltende Bedrohung auf mehreren Ebenen dar. Neben durchschnittlich ~37.000 Todesfällen pro Jahr verursachen meteorologische Katastrophen Eigentumsschäden und Wirtschaftsbeeinträchtigungen, wodurch die Lebensgrundlagen und der Wohlstand der Menschen untergraben werden. Während die globale Temperatur – verursacht durch anthropogene Treibhausgasemissionen – ansteigt, nehmen die direkten Auswirkungen klimatischer Extremereignisse zu und werden sich ohne geeignete Anpassungsmaßnahmen weiter verstärken. Hinzu kommt, dass Wetterextreme nicht nur lokal direkte Schäden anrichten, sondern sich wetterbedingte wirtschaftliche Auswirkungen auch entlang der Handelsketten ausbreiten und so indirekte Effekte nach sich ziehen. Ein Ansatz zur Analyse dieser indirekten Auswirkungen innerhalb des komplexen globalen Versorgungsnetzes ist das agentenbasierte Modell Acclimate. In meiner Dissertation verwende und erweitere ich dieses Schadenspropagationsmodell, um drei Aspekte der Beziehung zwischen Wetterextremen und wirtschaftlichen Auswirkungen zu untersuchen. Erstens verursachen extreme Wetterereignisse direkte Schäden in lokaler Wirtschaftsleistung. Die regionalen Auswirkungen werden auf der Grundlage von physikalischen Faktoren und lokalen Produktivitätsverteilungen kalkuliert. Ich berechne tägliche Zeitreihen lokaler Produktionsverluste durch Hitzestress, Überschwemmungen, tropische Wirbelstürme und deren konsekutives Auftreten unter Verwendung von Klimaprojektionsensembles. Die direkten Auswirkungen der oben genannten Katastrophenkategorien sind sehr heterogen in Bezug auf die regionale und zeitliche Verteilung. Ebenso ändert sich ihre Stärke unterschiedlich unter zukünftiger Erwärmung. Meine Forschungsergebnisse zeigen, dass Kapitalstock, welcher von Wirbelstürmen beschädigt ist, langfristige Wachstumsverluste verursacht. Dabei nehmen die Verluste zu, wenn die Heterogenität der Schocks steigt. Zweitens werden die wetterbedingten Auswirkungen durch wirtschaftliche Wellen innerhalb des Handelsnetzes auf verschiedene Wirtschaftssektoren und Regionen verteilt. In meiner Dissertation, untersuche ich die wirtschaftlichen Wellen mittels Acclimate und mache dabei drei Wellenphasen aus. Darüber hinaus berechne ich indirekte Auswirkungen und analysiere die regionalen und globalen Produktionsveränderungen sowie die Auswirkungen auf Konsumierende. Für letztere verdoppeln sich zwischen 2000 und 2039 die weltweiten Verluste durch Hitzestress, während im selben Zeitraum die direkten Produktionsverluste nur um den Faktor 1.5 steigen. Im Zuge meiner Forschung identifiziere ich den Effekt der ökonomischen Wellenresonanz und führe ihn in die Klimafolgenforschung ein. Dieser Effekt tritt auf, wenn sich die ökonomischen Wellen aufeinanderfolgender Katastrophen überlagern, was wirtschaftliche Reaktionen intensiviert wie beispielsweise eine Steigerung der Konsumverluste. Diese Dynamik der Verluste kann durch zunehmende direkte Produktionsverluste, hervorgerufen etwa durch den Klimawandel, noch verstärkt werden. Auch Handelsunterbrechungen können wirtschaftliche Auswirkungen haben. Um diese zu berechnen, erweitere ich das Modell Acclimate um ein geografisches Transportnetzwerk und weite den Entscheidungshorizont der Wirtschaftsakteure aus. Politisch bedingte plötzliche Handelsbeschränkungen (z. B. ein No-Deal-Brexit) können den längerfristigen wirtschaftlichen Wohlstand der betroffenen Regionen erheblich verringern. Analysen von Transportunterbrechungen in der Taifunsaison zeigen, dass stark betroffene Regionen ihre Produktionen reduzieren müssen, wenn die Nachfrage während eines Sturms sinkt. Zu Beginn eines Sturms können Handelsschwankungen durch alternative Lieferanten ausgeglichen werden, was jedoch bei längeren Unterbrechungen nicht mehr gelingt. Drittens ergeben sich mögliche Anpassungsmechanismen und -strategien aus direkten und indirekten wirtschaftlichen Reaktionen auf Wetterextreme. Die Analyse der jährlichen Handelsveränderungen in der Taifunsaison zeigt, dass Exporte insgesamt zunehmen. Diese Widerstandsfähigkeit des Handels wächst mit einer höheren Diversifizierung der Handelspartner. Weiterhin zeigt meine Forschung an Wirtschaftswachstumsmodellen, dass ein Versicherungssystem langfristige Wachstumsverluste, verursacht durch Tropenstürme, durch schnelleren Wiederaufbau verringern kann. Ich komme zu dem Schluss, dass ein Versicherungsschutz eine wirtschaftlich sinnvolle Anpassungsstrategie gegenüber höheren Schäden durch die Klimakrise sein kann. Ebenso weisen indirekte Auswirkungen von Wetterextremen innerhalb des globalen Wirtschaftsnetzes auf weitere Anpassungsmöglichkeiten hin. Zunächst vermindert eine diversifizierte Vernetzung die Gefahr eines starken Preisanstiegs. Ebenso kann eine enge wirtschaftliche Verflechtung von Regionen, die nicht dieselbe Unwettersaison haben, mittelfristig wirtschaftlich vorteilhaft sein. Weiterhin sollten bei der Berechnung der Kosten wirtschaftliche Resonanzeffekte berücksichtigt werden. Eine Verstärkung der lokalen Anpassungsmaßnahmen verringert die Amplitude ökonomischer Wellen und damit auch potentielle Verluste in anderen Regionen. Insgesamt sind Anpassungsmaßnahmen notwendig, aber es scheint trotz dieser nicht möglich zu sein, alle direkten oder indirekten Verluste zu vermeiden. Wie ich in meiner Arbeit darlege, gibt die dynamische Modellierung wertvolle Einblicke in die Art und Weise, wie direkte und indirekte wirtschaftliche Auswirkungen durch verschiedene Wetterextreme entstehen. Darüber hinaus wird deutlich, wie wichtig es ist, einzelne Extremereignisse aufzulösen und Verstärkungseffekte zu berücksichtigen, die durch unvollständigen Wiederaufbau oder aufeinanderfolgende Katastrophen verursacht werden. KW - climate change KW - weather extremes KW - macro-economic modelling KW - network theory KW - economic network KW - Klimawandel KW - Wetterextreme KW - Makroökonomische Modellierung KW - Netzwerktheorie KW - Ökonomisches Netzwerk Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-552668 ER - TY - JOUR A1 - Kunert, Nina A1 - Pang, Peter T. H. A1 - Tews, Ingo A1 - Coughlin, Michael W. A1 - Dietrich, Tim T1 - Quantifying modeling uncertainties when combining multiple gravitational-wave detections from binary neutron star sources JF - Physical review D N2 - With the increasing sensitivity of gravitational-wave detectors, we expect to observe multiple binary neutron-star systems through gravitational waves in the near future. The combined analysis of these gravitational-wave signals offers the possibility to constrain the neutron-star radius and the equation of state of dense nuclear matter with unprecedented accuracy. However, it is crucial to ensure that uncertainties inherent in the gravitational-wave models will not lead to systematic biases when information from multiple detections is combined. To quantify waveform systematics, we perform an extensive simulation campaign of binary neutron-star sources and analyze them with a set of four different waveform models. For our analysis with 38 simulations, we find that statistical uncertainties in the neutron-star radius decrease to 1250 m (2% at 90% credible interval) but that systematic differences between currently employed waveform models can be twice as large. Hence, it will be essential to ensure that systematic biases will not become dominant in inferences of the neutron-star equation of state when capitalizing on future developments. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevD.105.L061301 SN - 2470-0010 SN - 2470-0029 VL - 105 IS - 6 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Kupfer, Thomas A1 - Bauer, Evan B. A1 - van Roestel, Jan A1 - Bellm, Eric C. A1 - Bildsten, Lars A1 - Fuller, Jim A1 - Prince, Thomas A. A1 - Heber, Ulrich A1 - Geier, Stephan A1 - Green, Matthew J. A1 - Kulkarni, Shrinivas R. A1 - Bloemen, Steven A1 - Laher, Russ R. A1 - Rusholme, Ben A1 - Schneider, David T1 - Discovery of a Double-detonation Thermonuclear Supernova Progenitor JF - The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters N2 - We present the discovery of a new double-detonation progenitor system consisting of a hot subdwarf B (sdB) binary with a white dwarf companion with a P (orb) = 76.34179(2) minutes orbital period. Spectroscopic observations are consistent with an sdB star during helium core burning residing on the extreme horizontal branch. Chimera light curves are dominated by ellipsoidal deformation of the sdB star and a weak eclipse of the companion white dwarf. Combining spectroscopic and light curve fits, we find a low-mass sdB star, M (sdB) = 0.383 +/- 0.028 M (circle dot) with a massive white dwarf companion, M (WD) = 0.725 +/- 0.026 M (circle dot). From the eclipses we find a blackbody temperature for the white dwarf of 26,800 K resulting in a cooling age of approximate to 25 Myr whereas our MESA model predicts an sdB age of approximate to 170 Myr. We conclude that the sdB formed first through stable mass transfer followed by a common envelope which led to the formation of the white dwarf companion approximate to 25 Myr ago. Using the MESA stellar evolutionary code we find that the sdB star will start mass transfer in approximate to 6 Myr and in approximate to 60 Myr the white dwarf will reach a total mass of 0.92 M (circle dot) with a thick helium layer of 0.17 M (circle dot). This will lead to a detonation that will likely destroy the white dwarf in a peculiar thermonuclear supernova. PTF1 J2238+7430 is only the second confirmed candidate for a double-detonation thermonuclear supernova. Using both systems we estimate that at least approximate to 1% of white dwarf thermonuclear supernovae originate from sdB+WD binaries with thick helium layers, consistent with the small number of observed peculiar thermonuclear explosions. Y1 - 2022 U6 - https://doi.org/10.3847/2041-8213/ac48f1 SN - 2041-8205 SN - 2041-8213 VL - 925 IS - 2 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Kurilovich, Aleksandr A. A1 - Mantsevich, Vladimir N. A1 - Mardoukhi, Yousof A1 - Stevenson, Keith J. A1 - Chechkin, Aleksei A1 - Palyulin, Vladimir V. T1 - Non-Markovian diffusion of excitons in layered perovskites and transition metal dichalcogenides JF - Physical chemistry, chemical physics : a journal of European Chemical Societies N2 - The diffusion of excitons in perovskites and transition metal dichalcogenides shows clear anomalous, subdiffusive behaviour in experiments. In this paper we develop a non-Markovian mobile-immobile model which provides an explanation of this behaviour through paired theoretical and simulation approaches. The simulation model is based on a random walk on a 2D lattice with randomly distributed deep traps such that the trapping time distribution involves slowly decaying power-law asymptotics. The theoretical model uses coupled diffusion and rate equations for free and trapped excitons, respectively, with an integral term responsible for trapping. The model provides a good fitting of the experimental data, thus, showing a way for quantifying the exciton diffusion dynamics. Y1 - 2022 U6 - https://doi.org/10.1039/d2cp00557c SN - 1463-9076 SN - 1463-9084 VL - 24 IS - 22 SP - 13941 EP - 13950 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Kölsch, Maximilian A1 - Dietrich, Tim A1 - Ujevic, Maximiliano A1 - Brügmann, Bernd T1 - Investigating the mass-ratio dependence of the prompt-collapse threshold with numerical-relativity simulations JF - Physical review : D, Particles, fields, gravitation, and cosmology N2 - The next observing runs of advanced gravitational-wave detectors will lead to a variety of binary neutron star detections and numerous possibilities for multimessenger observations of binary neutron star systems. In this context a clear understanding of the merger process and the possibility of prompt black hole formation after merger is important, as the amount of ejected material strongly depends on the merger dynamics. These dynamics are primarily affected by the total mass of the binary, however, the mass ratio also influences the postmerger evolution. To determine the effect of the mass ratio, we investigate the parameter space around the prompt-collapse threshold with a new set of fully relativistic simulations. The simulations cover three equations of state and seven mass ratios in the range of 1.0 <= q <= 1.75, with five to seven simulations of binary systems of different total mass in each case. The threshold mass is determined through an empirical relation based on the collapse time, which allows us to investigate effects of the mass ratio on the threshold mass and also on the properties of the remnant system. Furthermore, we model effects of mass ratio and equation of state on tidal parameters of threshold configurations. Y1 - 2022 U6 - https://doi.org/10.1103/PhysRevD.106.044026 SN - 2470-0010 SN - 2470-0029 VL - 106 IS - 4 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Lai, Huagui A1 - Luo, Jincheng A1 - Zwirner, Yannick A1 - Olthof, Selina A1 - Wieczorek, Alexander A1 - Ye, Fangyuan A1 - Jeangros, Quentin A1 - Yin, Xinxing A1 - Akhundova, Fatima A1 - Ma, Tianshu A1 - He, Rui A1 - Kothandaraman, Radha K. A1 - Chin, Xinyu A1 - Gilshtein, Evgeniia A1 - Muller, Andre A1 - Wang, Changlei A1 - Thiesbrummel, Jarla A1 - Siol, Sebastian A1 - Prieto, Jose Marquez A1 - Unold, Thomas A1 - Stolterfoht, Martin A1 - Chen, Cong A1 - Tiwari, Ayodhya N. A1 - Zhao, Dewei A1 - Fu, Fan T1 - High-performance flexible all-Perovskite tandem solar cells with reduced V-OC-deficit in wide-bandgap subcell JF - Advanced energy materials N2 - Among various types of perovskite-based tandem solar cells (TSCs), all-perovskite TSCs are of particular attractiveness for building- and vehicle-integrated photovoltaics, or space energy areas as they can be fabricated on flexible and lightweight substrates with a very high power-to-weight ratio. However, the efficiency of flexible all-perovskite tandems is lagging far behind their rigid counterparts primarily due to the challenges in developing efficient wide-bandgap (WBG) perovskite solar cells on the flexible substrates as well as their low open-circuit voltage (V-OC). Here, it is reported that the use of self-assembled monolayers as hole-selective contact effectively suppresses the interfacial recombination and allows the subsequent uniform growth of a 1.77 eV WBG perovskite with superior optoelectronic quality. In addition, a postdeposition treatment with 2-thiopheneethylammonium chloride is employed to further suppress the bulk and interfacial recombination, boosting the V-OC of the WBG top cell to 1.29 V. Based on this, the first proof-of-concept four-terminal all-perovskite flexible TSC with a power conversion efficiency of 22.6% is presented. When integrating into two-terminal flexible tandems, 23.8% flexible all-perovskite TSCs with a superior V-OC of 2.1 V is achieved, which is on par with the V-OC reported on the 28% all-perovskite tandems grown on the rigid substrate. KW - all-perovskite tandems KW - flexible tandem solar cells KW - perovskite KW - V OC-deficit KW - wide-bandgap Y1 - 2022 U6 - https://doi.org/10.1002/aenm.202202438 SN - 1614-6832 SN - 1614-6840 VL - 12 IS - 45 PB - Wiley-VCH CY - Weinheim ER - TY - THES A1 - Laquai, René T1 - Extending synchrotron X-ray refraction techniques to the quantitative analysis of metallic materials N2 - In this work, two X-ray refraction based imaging methods, namely, synchrotron X-ray refraction radiography (SXRR) and synchrotron X-ray refraction computed tomography (SXRCT), are applied to analyze quantitatively cracks and porosity in metallic materials. SXRR and SXRCT make use of the refraction of X-rays at inner surfaces of the material, e.g., the surfaces of cracks and pores, for image contrast. Both methods are, therefore, sensitive to smaller defects than their absorption based counterparts X-ray radiography and computed tomography. They can detect defects of nanometric size. So far the methods have been applied to the analysis of ceramic materials and fiber reinforced plastics. The analysis of metallic materials requires higher photon energies to achieve sufficient X-ray transmission due to their higher density. This causes smaller refraction angles and, thus, lower image contrast because the refraction index depends on the photon energy. Here, for the first time, a conclusive study is presented exploring the possibility to apply SXRR and SXRCT to metallic materials. It is shown that both methods can be optimized to overcome the reduced contrast due to smaller refraction angles. Hence, the only remaining limitation is the achievable X-ray transmission which is common to all X-ray imaging methods. Further, a model for the quantitative analysis of the inner surfaces is presented and verified. For this purpose four case studies are conducted each posing a specific challenge to the imaging task. Case study A investigates cracks in a coupon taken from an aluminum weld seam. This case study primarily serves to verify the model for quantitative analysis and prove the sensitivity to sub-resolution features. In case study B, the damage evolution in an aluminum-based particle reinforced metal-matrix composite is analyzed. Here, the accuracy and repeatability of subsequent SXRR measurements is investigated showing that measurement errors of less than 3 % can be achieved. Further, case study B marks the fist application of SXRR in combination with in-situ tensile loading. Case study C is out of the highly topical field of additive manufacturing. Here, porosity in additively manufactured Ti-Al6-V4 is analyzed with a special interest in the pore morphology. A classification scheme based on SXRR measurements is devised which allows to distinguish binding defects from keyhole pores even if the defects cannot be spatially resolved. In case study D, SXRCT is applied to the analysis of hydrogen assisted cracking in steel. Due to the high X-ray attenuation of steel a comparatively high photonenergy of 50 keV is required here. This causes increased noise and lower contrast in the data compared to the other case studies. However, despite the lower data quality a quantitative analysis of the occurance of cracks in dependence of hydrogen content and applied mechanical load is possible. N2 - In der vorliegenden Arbeit werden die zwei, auf Refraktion basierende, Röntgenbildgebungsverfahren Synchrotron Röntgen-Refraktions Radiographie (engl.: SXRR) und Synchrotron Röntgen-Refraktions Computertomographie (engl.: SXRCT) für die quantitative Analyse von Rissen und Porosität in metallischenWerkstoffen angewandt. SXRR und SXRCT nutzen die Refraktion von Röntgenstrahlen an inneren Oberflächen des Materials, z.B. die Oberflächen von Rissen und Poren, zur Bildgebung. Beide Methoden sind daher empfindlich gegenüber kleineren Defekten als ihre auf Röntgenabsorption basierenden Gegenstücke, Röntgenradiographie und Röntgen-Computertomographie. Sie sind in der Lage Defekte von nanometrischer Größe zu detektieren. Bislang wurden die Methoden für die Analyse von keramischen Werkstoffen und faserverstärkten Kunststoffen eingesetzt. Die Analyse von metallischenWerkstoffen benötigt höhere Photonenenergien benötigt werden um eine ausreichende Transmission zu erreichen. Dies hat kleinere Refraktionswinkel, und damit geringeren Bildkontrast, zur Folge, da der Brechungsindex von der Photonenenergie abhängt. Hier wird erstmals eine umfassende Studie vorgelegt, welche die Möglichkeiten zur Untersuchung metallischer Werkstoffe mittels SXRR und SXRCT untersucht. Es wird gezeigt, dass der geringere Kontrast, verursacht durch die kleineren Refraktionswinkel, überwunden werden kann. Somit ist die einzig verbleibende Beschränkung die erreichbare Transmission, die alle Röntgenbildgebungsverfahren gemeinsam haben. Darüber hinaus wird ein Modell für die quantitative Auswertung der inneren Oberflächen präsentiert und verifiziert. Zu diesem Zweck werden vier Fallstudien durchgeführt, wobei jede eine spezifische Herausforderung darstellt. In Fallstudie A werden Risse in einer Probe aus einer Aluminiumschweißnaht untersucht. Diese Fallstudie dient hauptsächlich dazu das Modell für die quantitative Analyse zu verifizieren und die Empfindlichkeit gegenüber Strukturen unterhalb des Auflösungsvermögens zu beweisen. In Fallstudie B wird die Entwicklung der Schädigung in einem aluminiumbasierten partikelverstärktem Metall-Matrix Komposit untersucht. Dabei wird die Genauigkeit und Wiederholbarkeit der SXRR Messungen analysiert und es wird gezeigt das Messfehler kleiner 3% erreicht werden können. Darüber hinaus wird in Fallstudie B erstmals SXRR in Kombination mit in-situ Zugbelastung eingesetzt. Fallstudie C ist aus dem hochaktuellen Bereich der additive Fertigung. Hier wird Porosität in additiv gefertigtem Ti-Al6-V4 analysiert mit besonderem Augenmerk auf der Morphologie der Poren. Es wurde ein Verfahren zur Klassifizierung, basierend auf SXRR Messungen, erfunden, welches Bindefehler und Poren voneinander unterscheiden kann auch wenn die Defekte nicht räumlich aufgelöst werden können. In Fallstudie D wird SXRCT zur Analyse von wasserstoffunterstützter Rissbildung in Stahl angewandt. Wegen der hohen Röntgenschwächung des Stahls muss hier mit 50 keV eine vergleichsweise hohe Photonenenergie genutzt werden. Dadurch zeigen die Daten ein erhöhtes Rauschen und geringeren Kontrast verglichen mit den anderen Fallstudien. Allerdings ist es, trotz der geringeren Datenqualität, möglich das Auftreten von Rissen in Abhängigkeit der Wasserstoffkonzentration und mechanischen Belastung zu untersuchen. T2 - Erweiterung von Röntgenrefraktions-Bildgebungsmethoden auf die quantitative Analyse von metallischen Werkstoffen KW - X-ray refraction imaging KW - non-destructive evaluation KW - computed tomography KW - porosity analysis KW - crack detection KW - Röntgen-Refraktions Bildgebung KW - zerstörungfreie Prüfung KW - Computertomography KW - Porositätsanalyse KW - Risserkennung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-541835 ER - TY - JOUR A1 - Laquai, René A1 - Schaupp, Thomas A1 - Griesche, Axel A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Hannemann, Andreas A1 - Kannengiesser, Thomas A1 - Bruno, Giovanni T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging JF - Advanced engineering materials N2 - While the problem of the identification of mechanisms of hydrogen-assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. Herein, it is shown how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in the literature, but this time using a nondestructive technique, it is shown that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, it is deduced that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. It is shown that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and it is deduced that a significant crack propagation can only be observed short before rupture. KW - 2101 duplex stainless steel KW - computed tomography KW - fractography KW - hydrogen KW - embrittlement KW - microcracking KW - synchrotron radiation KW - X-ray refraction Y1 - 2022 U6 - https://doi.org/10.1002/adem.202101287 SN - 1527-2648 VL - 24 IS - 6 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Le Corre, Vincent M. A1 - Diekmann, Jonas A1 - Peña-Camargo, Francisco A1 - Thiesbrummel, Jarla A1 - Tokmoldin, Nurlan A1 - Gutierrez-Partida, Emilio A1 - Peters, Karol Pawel A1 - Perdigón-Toro, Lorena A1 - Futscher, Moritz H. A1 - Lang, Felix A1 - Warby, Jonathan A1 - Snaith, Henry J. A1 - Neher, Dieter A1 - Stolterfoht, Martin T1 - Quantification of efficiency losses due to mobile ions in Perovskite solar cells via fast hysteresis measurements JF - Solar RRL N2 - Perovskite semiconductors differ from most inorganic and organic semiconductors due to the presence of mobile ions in the material. Although the phenomenon is intensively investigated, important questions such as the exact impact of the mobile ions on the steady-state power conversion efficiency (PCE) and stability remain. Herein, a simple method is proposed to estimate the efficiency loss due to mobile ions via "fast-hysteresis" measurements by preventing the perturbation of mobile ions out of their equilibrium position at fast scan speeds (approximate to 1000 V s(-1)). The "ion-free" PCE is between 1% and 3% higher than the steady-state PCE, demonstrating the importance of ion-induced losses, even in cells with low levels of hysteresis at typical scan speeds (approximate to 100mv s(-1)). The hysteresis over many orders of magnitude in scan speed provides important information on the effective ion diffusion constant from the peak hysteresis position. The fast-hysteresis measurements are corroborated by transient charge extraction and capacitance measurements and numerical simulations, which confirm the experimental findings and provide important insights into the charge carrier dynamics. The proposed method to quantify PCE losses due to field screening induced by mobile ions clarifies several important experimental observations and opens up a large range of future experiments. KW - hysteresis KW - mobile ions KW - perovskite solar cells Y1 - 2021 U6 - https://doi.org/10.1002/solr.202100772 SN - 2367-198X VL - 6 IS - 4 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Lepri, Stefano A1 - Pikovsky, Arkady T1 - Phase-locking dynamics of heterogeneous oscillator arrays JF - Chaos, solitons & fractals : applications in science and engineering ; an interdisciplinary journal of nonlinear science N2 - We consider an array of nearest-neighbor coupled nonlinear autonomous oscillators with quenched ran-dom frequencies and purely conservative coupling. We show that global phase-locked states emerge in finite lattices and study numerically their destruction. Upon change of model parameters, such states are found to become unstable with the generation of localized periodic and chaotic oscillations. For weak nonlinear frequency dispersion, metastability occur akin to the case of almost-conservative systems. We also compare the results with the phase-approximation in which the amplitude dynamics is adiabatically eliminated. KW - Ginzburg-Landau lattice KW - Disorder KW - Localized chaos KW - Reactive coupling Y1 - 2022 U6 - https://doi.org/10.1016/j.chaos.2021.111721 SN - 0960-0779 SN - 1873-2887 VL - 155 PB - Elsevier CY - Oxford ER - TY - THES A1 - Lever, Fabiano T1 - Probing the ultrafast dynamics of 2-Thiouracil with soft x-rays T1 - Untersuchung der ultraschnellen Dynamik von 2-Thiouracil mit weicher Röntgenstrahlung N2 - Understanding the changes that follow UV-excitation in thionucleobases is of great importance for the study of light-induced DNA lesions and, in a broader context, for their applications in medicine and biochemistry. Their ultrafast photophysical reactions can alter the chemical structure of DNA - leading to damages to the genetic code - as proven by the increased skin cancer risk observed for patients treated with thiouracil for its immunosuppressant properties. In this thesis, I present four research papers that result from an investigation of the ultrafast dynamics of 2-thiouracil by means of ultrafast x-ray probing combined with electron spectroscopy. A molecular jet in the gas phase is excited with a uv pulse and then ionized with x-ray radiation from a Free Electron Laser. The kinetic energy of the emitted electrons is measured in a magnetic bottle spectrometer. The spectra of the measured photo and Auger electrons are used to derive a picture of the changes in the geometrical and electronic configurations. The results allow us to look at the dynamical processes from a new perspective, thanks to the element- and site- sensitivity of x-rays. The custom-built URSA-PQ apparatus used in the experiment is described. It has been commissioned and used at the FL24 beamline of the FLASH2 FEL, showing an electron kinetic energy resolution of ∆E/E ~ 40 and a pump-probe timing resolution of 190 f s. X-ray only photoelectron and Auger spectra of 2-thiouracil are extracted from the data and used as reference. Photoelectrons following the formation a 2p core hole are identified, as well as resonant and non-resonant Auger electrons. At the L 1 edge, Coster-Kronig decay is observed from the 2s core hole. The UV-induced changes in the 2p photoline allow the study the electronic-state dynamics. With the use of an Excited-State Chemical Shift (ESCS) model, we observe a ultrafast ground-state relaxation within 250 f s. Furthermore, an oscillation with a 250 f s period is observed in the 2p binding energy, showing a coherent population exchange between electronic states. Auger electrons from the 2p core hole are analyzed and used to deduce a ultrafast C −S bond expansion on a sub 100 f s scale. A simple Coulomb-model, coupled to quantum chemical calculations, can be used to infer the geometrical changes in the molecular structure. N2 - Das Verständnis von lichtinduzierten, molekularen Prozessen ist über die Physik hinaus in einem breiten Kondext für Medizin und Biochemie relevant. Die ultraschnellen, photophysikalischen Reaktionen mancher Moleküle können die chemische Struktur von DNA verändern und somit genetischen Code schädigen. So führt zum Beispiel die UV-Anregung von Thionukleobasen zu Läsionen der DNA in den Zellen. Dementsprechend zeigen Patienten ein erhöhtes Hautkrebsrisiko, wenn sie im Rahmen einer immunsuppressiven Therapie mit Thiouracil behandelt werden. In dieser Dissertation stelle ich vier Forschungsarbeiten vor, in denen die ultraschnellen, intramolekularen Dynamiken von 2-Thiouracil mittels ultraschneller Anregungs-Abfrage(Pump-Probe)-Röntgenelektronenspektroskopie untersucht werden. Die relevanten molekularen Dynamiken werden stark durch das Schwefelatom des Thiouracils beeinflusst. Die Element- und Ortsempfindlichkeit der verwendeten Röntgenstrahlung erlauben es, diese Prozesse experimentell zu untersuchen. Dafür werden 2-Thiouracil-Moleküle thermisch in einem Molekularstrahl in die Gasphase freigesetzt. Nachdem die Moleküle mit einem UV-Puls angeregt wurden, erfolgt zeitversetzt die Abfrage mit einem Röntgenpuls, der die Moleküle ionisiert. Die kinetische Energie der emittierten Photo- und Augerelektronen wird mit einem Elektronenspektrometer vom Typ ‘Magnetische Flasche’ gemessen. Die Energiespektren dieser Elektronen werden verwendet, um ein Modell von den UV-lichtinduzierten Veränderungen der geometrischen und elektronischen Konfigurationen der Moleküle zu erhalten. Für diese Experimente wird erstmalig eine speziell angefertigte Apparatur namens URSA-PQ verwendet und beschrieben. Sie wurde an der Beamline FL24 des Freie Elektronenlaser (FEL) FLASH2 in Betrieb genommen und verwendet. Aus den Daten werden reine Röntgenphoto- und Augerelektronenspektren des Schwefelatoms von 2-Thiouracil extrahiert und als Referenz verwendet. Die 2p- Photoelektronen werden identifiziert, ebenso wie resonante und nicht-resonante Augerelektronen, die bei dem Zerfall des 2p-Kernlochs entstehen. Die UV-induzierten Veränderungen der 2p-Photolinie ermöglichen es, die Dynamik des elektronischen Zustands zu untersuchen. Unter Verwendung eines ESCS-Modells (Excited-State Chemical Shift) beobachten wir eine ultraschnelle Grundzustandsrelaxation innerhalb von 250 f s. Auger-Elektronen aus dem Zerfall des 2p-Kernlochs im UV-angeregten 2-Thiouracil werden ebenfalls analysiert. Die Änderung ihrer kinetischen Energie deutet auf eine ultraschnelle C − S-Bindungsexpansion auf einer Skala von unter 100 f s hin. Ein einfaches Coulomb-Modell, gekoppelt mit quantenchemischen Berechnungen, kann die geometrischen Veränderungen in der Molekülstruktur erklären. KW - Quantum KW - x-ray KW - photoelectron spectroscopy KW - thiouracil KW - nucleobases KW - Free Electron Laser KW - ultrafast KW - conical intersection KW - molecular dynamics KW - Freie-Elektronen-Laser KW - Quantum KW - konische Kreuzung KW - Molekulardynamik KW - Nukleobasen KW - Photoelektronenspektroskopie KW - Thiouracil KW - ultraschnell KW - Röntgenspektroskopie Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-555230 ER - TY - JOUR A1 - Lewenstein, Maciej A1 - Cirauqui, David A1 - Angel Garcia-March, Miguel A1 - Corominas, Guillem Guigo A1 - Grzybowski, Przemyslaw A1 - Saavedra, Jose R. M. A1 - Wilkens, Martin A1 - Wehr, Jan T1 - Haake-Lewenstein-Wilkens approach to spin-glasses revisited JF - Journal of physics : A, Mathematical and theoretical N2 - We revisit the Haake-Lewenstein-Wilkens approach to Edwards-Anderson (EA) model of Ising spin glass (SG) (Haake et al 1985 Phys. Rev. Lett. 55 2606). This approach consists in evaluation and analysis of the probability distribution of configurations of two replicas of the system, averaged over quenched disorder. This probability distribution generates squares of thermal copies of spin variables from the two copies of the systems, averaged over disorder, that is the terms that enter the standard definition of the original EA order parameter, qEA 0 0 KW - Edwards-Anderson order parameter KW - Haake-Lewenstein-Wilkens approach KW - spin glass KW - Saddle Point KW - Steppest Descend method Y1 - 2022 U6 - https://doi.org/10.1088/1751-8121/ac9d10 SN - 1751-8113 SN - 1751-8121 VL - 55 IS - 45 PB - IOP Publ. Ltd. CY - Bristol ER -