593 research outputs found
What is “Language Making”?
This article introduces a new concept called “Language Making”. The term covers all kinds of processes in which speakers or non-speakers collectively conceptualize linguistic entities. Such processes are usually perpetual, they operate based on language ideologies and attitudes, and they bring about functional and structural norms which determine the boundaries of linguistic entities such as languages, dialects or varieties. The article discusses the significance of standardization, language policy and planning, and of stakeholders and agency for processes of Language Making. Raising the question as to why a new concept is needed in the first place, the article concludes with a demarcation of Language Making from opposite processes which may be called “un-Making” of Languages
Identifying the oxygen evolution mechanism by microkinetic modelling of cyclic voltammograms
Electrocatalytic water splitting is currently one of the most promising reactions to produce “green” hydrogen in a decarbonized energy system. Its bottleneck reaction, the oxygen evolution reaction (OER), is catalysed by hydrous iridium, a stable and active catalyst material. Improving the OER requires a better and especially quantitative understanding of the reaction mechanism as well as its kinetics. In this work, we present an experimentally validated microkinetic model that allows to quantify the mechanistic pathways, emerging surface species prior and during the OER, the reaction rates for the single steps and essential thermodynamic properties. Therefore, two mechanisms based on density functional theory and experimental findings are evaluated on which only simulation results of the theory-based one are found to be in full accordance with cyclic voltammograms even at different potential rates and, thus, able to describe the catalytic system. The simulation implies that oxygen is evolving mostly via a fast single site pathway (∗OO → ∗ + O2 ) with an effective reaction rate, which is several orders of magnitude faster compared to the slow dual site (2∗ O → 2∗ + O2) pathway rate. Intermediate states of roughly 7% Ir(III), 25% Ir(IV) and 63% Ir(V) are present at typical OER potentials of 1.6 V vs RHE. We are able to explain counterintuitive experimental findings of a reduced iridium species during highly oxidizing potentials by the kinetic limitation of water adsorption. Although water adsorption is in general thermodynamically favourable, it is kinetically proceeding slower than the electrochemical steps at high potential. In the lower potential range from 0.05 to 1.5 V vs RHE the stepwise oxidation of the iridium is accompanied with van der Waals like ad- and desorption processes, which leads in comparison to Langmuir-type adsorption to a broadened peak shape in the cyclic voltammograms. Overall, our analysis shows that the dynamic microkinetic modelling approach is a powerful tool to analyse catalytic microkinetics in depth and to bridge the gap between thermodynamic calculations and experiments
Effects of agricultural practices on foraging habitats of a seabird species in the Baltic Sea
Omnivorous and opportunistic species may be good indicators of food availability. Gulls often use human-impacted landscapes and may respond to changes by altering their feeding ecology. We investigated the foraging behavior of individual common gulls (Larus canus), focusing on their distribution during foraging and their selected habitat types. We tracked adult common gulls using GPS telemetry at their largest breeding colony in the southwestern Baltic Sea, Germany. Foraging habitats were analyzed from tracking data for three breeding seasons 2016, 2017, and 2019 and were compared with potentially available foraging habitats. Most breeding birds flew toward terrestrial areas. Feeding sites were located on average 11.7-14.3 km from the colony (range 0.9-36.5 km). Corn and sugar beet fields were used significantly and extensively compared with their availability in 2016 and 2017, while wheat, rape, and barley fields were used significantly less. Data from 2019 suggested seasonal shifts in habitat use. Birds spent between 30 and 1300 min per week at their preferred feeding sites, with significant differences between the major habitats selected. We found a stable, clear, multiyear pattern in common gull foraging behavior in relation to agricultural practices. Fields with little or no crop cover and thus access to the soil were preferred over fields with high crop cover. These results suggest that local food availability may be limiting further population increases in this species
The Effects of Gas Saturation of Electrolytes on the Performance and Durability of Lithium‐Ion Batteries
Traces of species in batteries are known to impact battery performance. The effects of gas species, although often reported in the electrolyte and evolving during operation, have not been systematically studied to date and are therefore barely understood. This study reveals and compares the effects of different gases on the charge-discharge characteristics, cycling stability and impedances of lithium-ion batteries. All investigated gases have been previously reported in lithium-ion batteries and are thus worth investigating: Ar, CO, CO, CH, CH, H, CH and O. Gas-electrolyte composition has a significant influence on formation, coulombic and energy efficiencies, C-rate capability, and aging. Particularly, CO and O showed a higher C-rate capability and a decrease in irreversible capacity loss during the first cycle compared to Ar. Similar discharge capacities and aging behaviors are observed for CO, CH and CH. Acetylene showed a large decrease in performance and cycle stability. Furthermore, electrochemical impedance spectroscopy revealed that the gases mainly contribute to changes in charge transfer processes, whereas the effects on resistance and solid electrolyte interphase performance were minor. Compared to all other gas–electrolyte mixtures, the use of CO saturated electrolyte showed a remarkable increase in all performance parameters including lifetime
Microkinetic Barriers of the Oxygen Evolution on the Oxides of Iridium, Ruthenium and their Binary Mixtures
The performance of electrocatalytic water splitting in polymer electrolyte membrane electrolysis is substantially determined by the microkinetic processes of the oxygen evolution reaction (OER). Even highly active catalysts such as the nanoparticulated transition metal oxides IrO, RuO and their mixtures, IrRuO, exhibit overpotentials up to several hundreds of millivolts. The surface of the oxide mixtures IrRuO is found to consist of actives sites of both Ir and Ru on which the OER mechanism is processed independently and at different overpotentials. By applying microkinetic modelling and parameterization via cyclic voltammograms we show that there is a correlation between performance and the relative Ir content, that can be explained by two different deprotonation steps. These are in particular the formation of the adsorbate species *OOH on rutile RuO and *OO on IrO. The respective free reaction energies are quantified to 1.44 eV and 1.58 eV, which are the highest values of the process and thus determining the overpotential. The additional finding of adsorbed oxygen *O covering >40 % of the active sites during the OER suggests that subsequent water adsorption is the major performance limiting step. Finally, a synergetic effect between both active sites on the binary transition metal oxides is identified: the respective other metal lowers the potential determining reaction energy on the Ru or Ir active site. This insight into the surface processes on Ir and Ru binary oxides forms the basis for deeper understanding of the active sites for further OER catalyst development
In Stadt und Stadt: Berlin und Ruhrgebiet im Vergleich
The largest and most important urban centres in Germany, Berlin and the Ruhr metropolitan area, share a very similar socio-historical and linguistic past. The vernaculars spoken in these regions are both High German varieties that have developed on Low German substratum. Thus, both varieties have emerged from a language-shift situation and have preserved a number of Low German features. Moreover, both varieties have lost in prestige during the process of massive immigration during the period of industrialisation in the second half of the 19th century. In such contexts, processes of “dialect levelling” are to be expected. Then as now both the Ruhr area and Berlin are hotspots of urban multilingualism and national and international mobility. This lends both linguistic settings a special dynamics and innovative potential. In the light of these parallels it is promising to compare linguistic structures of these varieties in order to gauge whether similar conditions yield similar linguistic developments.
In this paper we investigate two syntactic phenomena which are highly salient both in the Berlin dialect and in Ruhr German. Using corpus data of spoken language we compare frequencies and formal features of (i) preposition-determiner cliticisation, and (ii) split pronominal adverbs in both varieties. As an overall result it can be stated that both phenomena show up more pronouncedly and more straigtforwardly in Ruhr German than in the Berlin dialect; thus it can be surmised that the latter follows the same path as the former, but has not yet reached the “final destination”
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