Technische Universität Darmstadt

About: Technische Universität Darmstadt is a education organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Neutron & Finite element method. The organization has 17316 authors who have published 40619 publications receiving 937916 citations. The organization is also known as: Darmstadt University of Technology & University of Darmstadt.

High-Strain Lead-free Antiferroelectric Electrostrictors

Abstract: Research on lead-free piezoceramics has dramatically increased over the last years due to stringent legislation demanding to phase out current lead- containing piezoceramics. The use of electrostrictive materials for electric-field induced strain has been largely overlooked. In this paper we demonstrate that electrostrictive materials around a ferroelectric-antiferroelectric transition are capable of providing high strains over a wide temperature regime that was not accessible before.

Evaluation of instant light-response curves of chlorophyll fluorescence parameters obtained with a portable chlorophyll fluorometer on site in the field

Abstract: Miniaturized pulse-amplitude modulated photosynthesis yield analysers are primarily designed for measuring effective quantum yield (ΔF/Fm′) of photosystem II under momentary ambient light conditions in the field. Although this provides important ecophysiological information, it is often necessary to learn more about the potential intrinsic capacities of leaves by measuring light-response curves. Thus, instruments provide light-curve programmes, where light intensities are increased in short intervals and instant light-response curves are recorded within a few minutes. This method can be criticized because photosynthesis will most likely not be in steady state. This technical report shows that with the appropriate precautions instant light curves can nevertheless provide reliable information about cardinal points of photosynthesis. First, the geometry of the light source of the instrument in relation to the quantum sensor must be considered and quantum sensor readings must be corrected. Second, the measurements of the light-response curves must be compared with readings of effective quantum yield of photosystem II under ambient light conditions where photosynthesis is in steady state. This may show that in the critical range of the light curves either both measurements perfectly coincide or are offset against each other by a constant value (examples are given here). In the first case results of light curves can be taken at face values, and in the second case a simple correction can be applied. With these precautions and careful interpretations instant light-response curves can be an enormous advantage in ecophysiological field work.

Computational Analysis Methods in Atomistic Modeling of Crystals

Abstract: This article discusses computational analysis methods typically used in atomistic modeling of crystalline materials and highlights recent developments that can provide better insights into processes at the atomic scale. Topics include the classification of local atomic structures, the transition from atomistics to mesoscale and continuum-scale descriptions, and the automated identification of dislocations in atomistic simulation data.

Identifying Argumentative Discourse Structures in Persuasive Essays

Abstract: In this paper, we present a novel approach for identifying argumentative discourse structures in persuasive essays. The structure of argumentation consists of several components (i.e. claims and premises) that are connected with argumentative relations. We consider this task in two consecutive steps. First, we identify the components of arguments using multiclass classification. Second, we classify a pair of argument components as either support or non-support for identifying the structure of argumentative discourse. For both tasks, we evaluate several classifiers and propose novel feature sets including structural, lexical, syntactic and contextual features. In our experiments, we obtain a macro F1-score of 0.726 for identifying argument components and 0.722 for argumentative relations.

Fundamental degradation mechanisms of layered oxide Li-ion battery cathode materials: Methodology, insights and novel approaches

Abstract: This overview addresses the atomistic aspects of degradation of layered LiMO2 (M = Ni, Co, Mn) oxide Li-ion battery cathode materials, aiming to shed light on the fundamental degradation mechanisms especially inside active cathode materials and at their interfaces. It includes recent results obtained by novel in situ/in operando diffraction methods, modelling, and quasi in situ surface science analysis. Degradation of the active cathode material occurs upon overcharge, resulting from a positive potential shift of the anode. Oxygen loss and eventual phase transformation resulting in dead regions are ascribed to changes in electronic structure and defect formation. The anode potential shift results from loss of free lithium due to side reactions occurring at electrode/electrolyte interfaces. Such side reactions are caused by electron transfer, and depend on the electron energy level alignment at the interface. Side reactions at electrode/electrolyte interfaces and capacity fade may be overcome by the use of suitable solid-state electrolytes and Li-containing anodes.