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Aufsatz
Effects of mucilage concentration at different water contents on mechanical stability and elasticity in a loamy and a sandy soil
(2021-10-26)
Mucilage released by plant roots affects hydrological and mechanical properties of the rhizosphere. The aim of this study was to disentangle the effects of the factors mucilage and soil moisture on a range of soil mechanical parameters in a sand and a loam. Both substrates were homogenised and filled into cylinders at bulk densities (ρb) of 1.26 and 1.47 g cm−³ for loam and sand, respectively. Chia seed (Salvia hispanica L.) mucilage concentrations of 0, 0.02, 0.2 and 2 g dry mucilage kg−¹ dry soil were tested at ...
Aufsatz
Synthesis, Structure and Cu-Phenylacetylide Coordination of an Unsymmetrically Substituted Bulky dppf-Analog
(2021-12-03)
The donor properties of a set of bulky ferrocene based bisphosphanes (Fe(C₅H₄PMes₂)₂ and (C₅H₄PMes₂)Fe(C₅H₄PᵗBu₂ with Mes= mesityl and ᵗBu=tert-butyl) were probed by exploring the NMR parameters of the corresponding selenophosphoranes amended by cyclovoltammetry. The ligand properties were explored in the complexation of copper phenylacetylide which is relevant as intermediate in the Cu(I) catalyzed CO₂ addition to phenylacetylene. Owing to the poor solubility of the resulting complexes their characterization was ...
Aufsatz
CLeaR: An adaptive continual learning framework for regression tasks
(2021-07-16)
Catastrophic forgetting means that a trained neural network model gradually forgets the previously learned tasks when being retrained on new tasks. Overcoming the forgetting problem is a major problem in machine learning. Numerous continual learning algorithms are very successful in incremental learning of classification tasks, where new samples with their labels appear frequently. However, there is currently no research that addresses the catastrophic forgetting problem in regression tasks as far as we know. This ...
Buch
Transnationaler Bergbau und lokale Politik
(transcript, 2022)
Diese Arbeit stellt die Interaktionsbeziehungen zwischen Bergbauunternehmen, den politischen Vertreter:innen sowie Vertreter:innen weiterer Einrichtungen aus dem Bildungsbereich und lokaler Wirtschaftssektoren in den Gemeinden in den Abbauregionen industrieller Minen in den Fokus der Untersuchung.
Ziel der vorliegenden Arbeit ist es, das Handeln transnationaler Bergbauunternehmen in lokalen Politikarenen zu analysieren. Eine solche Untersuchung soll Erklärungsansätze dafür entwickeln, welche Strategien Bergbauunternehmen ...
Aufsatz
On a hybrid approximation concept for self-excited periodic oscillations of large-scale dynamical systems
(2021-12-14)
When approximating periodic solutions in the context of large-scale dynamical systems involving strong local nonlinearities, efficiency is of special interest. Hence, the literature suggests a combination of two approximation methods for increasing the ratio of computational cost to accuracy. Within this contribution, a combination of Finite Difference and Harmonic Balance method is proposed. Due to the usage of Harmonic Balance it is shown, that the resulting equations only depend on the degrees of freedom that are ...
Aufsatz
Resolving the base of the pyramid inclusion paradox through supplier development
(2021-05-16)
Resulting from divergent business environments between actors, the integration of the base of the pyramid (BoP) into formal supply chain (SC) structures is often hampered by institutional voids, which can result in the emergence of paradoxical situations. This paper analyzes the potential of supplier development (SD) for addressing the BoP inclusion paradox. The study develops a framework based on the assumption that SD enables the development of capabilities and supplier performance, which is especially relevant ...
Aufsatz
Environmental and Economic Performance of CO₂-Based Methanol Production Using Long-Distance Transport for H₂ in Combination with CO₂ Point Sources: A Case Study for Germany
(2022-03-29)
The use of CO₂-based hydrocarbons plays a crucial role in reducing the climate footprint for several industry sectors, such as the chemical industry. Recent studies showed that regions which are favorable for the production of CO₂-based hydrocarbons from an energy perspective often do not provide concentrated point sources for CO₂, which leads to an increased environmental impact due to the higher energy demand of direct air capture processes. Thus, producing H2 in regions with high renewable power potential and ...
Aufsatz
Numerical simulation of flow processes of wood‐polymer in extrusion dies
(2021-01-25)
The addition of wood to polymers results in wood‐polymer composites (WPC), whereby the wood content can be up to 80 %. This composite is mainly processed in extruded deckings. The extrusion die is an essential part of the process, which determines both process parameters and the final product. A characteristic of WPC extrusion dies is a partial solidification of the melt before leaving the die. This solidification is necessary to ensure a dimensionally stable extrusion. For the design of WPC extrusion dies numerical ...
Aufsatz
Signaling of Pigment-Dispersing Factor (PDF) in the Madeira Cockroach Rhyparobia maderae
(2014)
The insect neuropeptide pigment-dispersing factor (PDF) is a functional ortholog of vasoactive intestinal polypeptide, the coupling factor of the mammalian circadian pacemaker. Despite of PDF's importance for synchronized circadian locomotor activity rhythms its signaling is not well understood. We studied PDF signaling in primary cell cultures of the accessory medulla, the circadian pacemaker of the Madeira cockroach. In Ca2+ imaging studies four types of PDF-responses were distinguished. In regularly bursting type ...
Aufsatz
Squeezed thermal phonons precurse nonthermal melting of silicon as a function of fluence
(2013)
A femtosecond-laser pulse can induce ultrafast nonthermal melting of various materials along pathways
that are inaccessible under thermodynamic conditions, but it is not known whether there is any structural
modification at fluences just below the melting threshold. Here, we show for silicon that in this regime the
room-temperature phonons become thermally squeezed, which is a process that has not been reported
before in this material. We find that the origin of this effect is the sudden femtosecond-laser-induc ...