Begutachtungsverfahren als wissenschaftliche Qualitätssicherung Ein Erfahrungsbericht aus internationaler Gutachter- und Veröffentlichungspraxis

Unterschiedliche Fächer haben unterschiedliche Fachkulturen, was sich u.a. auch in der Publikationskultur niederschlägt. Während in einigen Fächern der zentrale Publikationsweg über Monographien läuft, hat sich in der Mathematikdidaktik immer mehr eine Publikationskultur über Zeitschriften entwickelt. Dabei werden die wichtigsten wissenschaftlichen Ansätze und Ergebnisse über wissenschaftliche Zeitschriften mit Begutachtungsverfahren publiziert und diskutiert [...]

Recent progress and emerging application areas for lithium-sulfur battery technology

Electrification is progressing significantly within the present and future vehicle sectors such as large commercial vehicles (e. g. trucks and busses), high altitude long endurance (HALE), high altitude pseudo satellites (HAPS), and electric vertical take‐off and landing (eVTOL). The battery systems performance requirements differ across these applications in terms of power, cycle life, system cost, etc. However, the need for high gravimetric energy density, 400 Wh kg−1 and beyond, is common across them all, since it will enable vehicles to achieve extended range, longer mission duration, lighter weight or increased payload. The system level requirements of these emerging applications can be broken down into the component level developments required to integrate Li‐S technology as the power system of choice. In order to adapt the batteries’ properties, such as energy and power density, to the respective application, the academic research community has a key role to play in component level development. However, materials and component research must be conducted within the context of a viable Li‐S cell system. Herein, the key performance benefits, limitations, modelling and recent progress of the Li‐S battery technology and its adaption towards real world application are discusse

IST Austria Technical Report

With the lithium-ion technology approaching its intrinsic limit with graphite-based anodes, lithium metal is recently receiving renewed interest from the battery community as potential high capacity anode for next-generation rechargeable batteries. In this focus paper, we review the main advances in this field since the first attempts in the mid-1970s. Strategies for enabling reversible cycling and avoiding dendrite growth are thoroughly discussed, including specific applications in all-solid-state (polymeric and inorganic), Lithium-sulphur and Li-O2 (air) batteries. A particular attention is paid to review recent developments in regard of prototype manufacturing and current state-ofthe-art of these battery technologies with respect to the 2030 targets of the EU Integrated Strategic Energy Technology Plan (SET-Plan) Action 7

Mechanistic insights into the reversible lithium storage in an open porous carbon via metal cluster formation in all solid-state batteries

Porous carbons are promising anode materials for next generation lithium batteries due to their large lithium storage capacities. However, their highsloping capacity during lithiation and delithiation as well as capacity fading due to intense formation of solid electrolyte interphase (SEI) limit their gravimetric and volumetric energy densities. Herein we compare a microporous carbide derived carbon material (MPC) as promising future anode for all solid state batteries with a commercial high performance hard carbon anode. The MPC obtains high and reversible lithiation capacities of 1000 mAh g 1 carbon in half cells exhibiting an extended plateau region near 0 V vs. Li/Liþ preferable for full cell application. The well defined microporosity of the MPC with a specific surface area of >1500 m2 g 1 combines well with the argyrodite type electrolyte (Li6PS5Cl) suppressing extensive SEI formation to deliver high coulombic efficiencies. Preliminary full cell measurements vs. nickel rich NMC cathodes (LiNi0.9Co0.05Mn0.05O2) provide a considerably improved average potential of 3.76 V leading to a projected energy density as high as 449 Wh kg 1 and reversible cycling for more than 60 cycles. 7Li Nuclear Magnetic Resonance spectroscopy was combined with ex situ Small Angle X ray Scattering to elucidate the storage mechanism of lithium inside the carbon matrix. The formation of extended quasi metallic lithium clusters after electrochemical lithiation was revealed

Die Entwicklung der Lesekompetenz von der frühen Kindheit bis zum Jugendalter. Empirische Befunde aus den Bamberger BiKS-Längsschnittstudien

The BiKS research group (“Educational processes, competence development, and selection decisions in preschool- and school age”) founded in 2005 and financed by the German Research Foundation (DFG), was established by a consortium of researchers combining expertise from the disciplines of psychology, education, and sociology. Two longitudinal studies were being conducted by the BiKS research group and followed until 2012. In the first study, a cohort of preschool children was traced until grade 4 in primary school. The second study comprises a cohort of primary school children who were followed until their 9th grade in secondary school. Besides the multidisciplinary perspective, the studies can be well characterized by their broad use of different methods, such as test data, interviews, questionnaires, and live observations of behaviour as well as a consideration of different agents, i.e. students, parents, and teachers. The book focuses on empirical research findings concerning the development of reading literacy from a longitudinal perspective and the chapters cover findings from both longitudinal studies of the BiKS research group. As authors from different academic disciplines have contributed, this volume covers a range of psychological, educational as well as sociological perspectives on causes and effects of stability and interindividual differences in the development of reading literacy.Die DFG-finanzierte Bamberger Forschergruppe BiKS („Bildungsprozesse, Kompetenzentwicklung und Selektionsentscheidungen im Vorschul- und Schulalter“) wurde im Jahr 2005 gegründet und setzt sich aus einer Gruppe von Wissenschaftlern aus der Psychologie, der Erziehungswissenschaft und der Soziologie zusammen. Die Forschergruppe hat zwei Längsschnitte etabliert. Die Startstichprobe des ersten Längsschnittes umfasst Kinder, die zu Beginn der Studie den Kindergarten besuchten und überwiegend im Schuljahr 2008/2009 eingeschult wurden. Die zweite Längsschnittkohorte von Schülerinnen und Schülern besuchte zu Beginn der Studie die dritte Klasse der Grundschule und wechselte im Regelfall zum Schuljahr 2007/2008 in die Sekundarstufe. Ein charakteristisches Merkmal der Studien ist, neben ihrer interdisziplinären Ausrichtung, ein breites Spektrum an Erhebungsinstrumenten - unter anderem Verhaltensbeobachtungen, Leistungstests und Fragebögen - und Perspektiven. Das vorliegende Buch fasst empirische Ergebnisse zum Erwerb schriftsprachlicher Kompetenzen aus beiden Längsschnitten zusammen. Die Analysen umfassen Befunde zur Rolle der Vorschule und Schule für die Entwicklung der Lesekompetenz ebenso wie Auswertungen zu den Einflüssen der Eltern und der familiären Lernumwelten sowie der individuellen Interessen der Schülerinnen und Schüler

Topochemical conversion of an imine-into a thiazole-linked covalent organic framework enabling real structure analysis

Stabilization of covalent organic frameworks (COFs) by post-synthetic locking strategies is a powerful tool to push the limits of COF utilization, which are imposed by the reversible COF linkage. Here we introduce a sulfur-assisted chemical conversion of a two-dimensional imine-linked COF into a thiazole-linked COF, with full retention of crystallinity and porosity. This post-synthetic modification entails significantly enhanced chemical and electron beam stability, enabling investigation of the real framework structure at a high level of detail. An in-depth study by electron diffraction and transmission electron microscopy reveals a myriad of previously unknown or unverified structural features such as grain boundaries and edge dislocations, which are likely generic to the in-plane structure of 2D COFs. The visualization of such real structural features is key to understand, design and control structure-property relationships in COFs, which can have major implications for adsorption, catalytic, and transport properties of such crystalline porous polymers

Holocene fire activity during low-natural flammability periods reveals scale-dependent cultural human-fire relationships in Europe

Fire is a natural component of global biogeochemical cycles and closely related to changes in human land use. Whereas climate-fuel relationships seem to drive both global and subcontinental fire regimes, human-induced fires are prominent mainly on a local scale. Furthermore, the basic assumption that relates humans and fire regimes in terms of population densities, suggesting that few human-induced fires should occur in periods and areas of low population density, is currently debated. Here, we analyze human-fire relationships throughout the Holocene and discuss how and to what extent human driven fires affected the landscape transformation in the Central European Lowlands (CEL). We present sedimentary charcoal composites on three spatial scales and compare them with climate model output and land cover reconstructions from pollen records. Our findings indicate that widespread natural fires only occurred during the early Holocene. Natural conditions (climate and vegetation) limited the extent of wildfires beginning 8500 cal. BP, and diverging subregional charcoal composites suggest that Mesolithic hunter-gatherers maintained a culturally diverse use of fire. Divergence in regional charcoal composites marks the spread of sedentary cultures in the western and eastern CEL The intensification of human land use during the last millennium drove an increase in fire activity to early-Holocene levels across the CEL Hence, humans have significantly affected natural fire regimes beyond the local scale - even in periods of low population densities - depending on diverse cultural land-use strategies. We find that humans have strongly affected land-cover- and biogeochemical cycles since Mesolithic times

High Power supercap electrodes based on vertical aligned CNTs on Aluminum

A scalable process at atmospheric pressure for direct growth of vertical aligned carbon nanotube (VA-CNT) on aluminum substrates has been developed including dip-coating steps for the wet-chemical buffer and catalyst layer deposition and a subsequent chemical vapor deposition step. Up to 80 µm high vertical aligned carbon nanotube forests were obtained on catalyst-coated aluminium foil in a thermal plasma-free CVD process at atmospheric pressure and 645°C using ethene as carbon source. The influence of two catalyst compositions (Fe:Co 2:3 and Fe:Mo 47:3) and the effect of the catalyst concentration on growth rate, morphology and density of resulting CNT films were investigated. Additionally, the binder-free VA-CNT/aluminum system was electrochemically tested as supercap electrode and the feasibility of tailoring the specific capacity varying the catalyst layer thicknesses was shown. Electrochemical characteristics of supercapacitor cells made from VA-CNT/aluminum electrodes have been described in detail. The specific capacitance of electrodes deduced from impedance spectra varied between 25.6-61.2 F g-1 depending on the catalyst complex mixture composition and concentration. The VA-CNT/Al electrodes have a very low value of effective serial resistance (0.42-0.15 mOhm g) indicating a potential candidate as electrode material for high power supercapacitor application. Excellent cycle stability of supercapacitors has been demonstrated up to 300,000 cycles

Silicon carbon void structures as anode material for advanced lithium-ion and lithium-sulfur batteries: Paper presented at 7th International Conference on Carbon for Energy Storage and Environment Protection, CESEP 2017, Lyon, 23.-26.10.2017

Due to its high theoretical gravimetric capacity (3590 Ah kg-1 Li15Si4) and its low working potential, silicon is an attractive candidate to at least partially substitute the graphite anode material in state of the art lithium-ion batteries in order to achieve higher energy densities [1]. Additionally, the cycle life of lithium-sulfur batteries mainly suffers from the instable lithium anode. Lithiated silicon could be a more stable alternative preventing dendrite formation and electrolyte decomposition for that next generation battery cell type [2]. During the lithiation process of silicon a large undesirable volume expansion occurs generally known from other lithium alloys [1]. This volume expansion/contraction leads to the degradation of the entire anode and fast capacity fading. Nanostructured silicon carbon composites with free volume between the silicon core and the carbon shell could potentially compensate the volume change and ensure a stabile SEI at the surface of the carbon shell preventing electrolyte consumption during cycling. According to the recently published references, these void structures are mainly generated using silica templates which deliver a precise control of the void structure, but need to be removed by toxic hydrofluoric acid and laborious washing steps [3]. In this work an easily scalable process without this step is presented in order to gain a free volume between silicon and the carbon shell. The void structure results from the removal of a sacrificial template layer on the surface of commercially available silicon particles during the carbonization of the silicon carbon composite within a concerted process