Search

Stable radicals in organic conjugated molecules are of great interest due to their magnetic signals and broad optical absorptions. In this paper, we report on naphthalene, benzoperylene, perylene, terrylene, and quaterrylene carboximides, reduced under controlled conditions, where stable metal-free solid salts of radical anions could be obtained forming darkly colored solutions with line-rich UV/Vis/NIR spectra and exhibiting special magnetic properties. The most bathochromic shift of the absorption maxima extend from 760 until 1700 nm. Persistent paramagnetic properties of the solids were observed and temperature-dependent susceptibilities are measured. Graphical abstract

Die Software-Qualität ist ein wichtiger Faktor, der über den Erfolg oder Misserfolg eines Software-Produkts entscheidet. Der Vorteil ist, dass sich Software-Qualität bereits in den frühesten Phasen der Entwicklung manifestiert und anhand statischer Analysen gemessen werden kann. Der Nachteil ist, dass die Messergebnisse solcher statischer Analysen manuell interpretiert und bewertet werden müssen, um qualitative Aussagen über die interne Software-Qualität zu ermöglichen. In dieser Arbeit wird daher ein Ansatz vorgestellt, der die Bewertung der Messergebnisse statischer Analysen automatisiert. Dabei handelt es sich um eine Benchmark-orientierte Bewertung, bei der die Messergebnisse eines zu untersuchenden Software-Produkts mit den Messergebnissen von Referenz-Produkten verglichen wird. Anhand dieser Vergleiche wird ein sogenannter Quality-Score formuliert, der angibt, inwieweit das zu untersuchende Software-Produkt implizite Anforderungen erfüllt. Das Ergebnis dieser Arbeit ist ein Tool, das diesen Ansatz implementiert. Software quality is an important factor for the success or failure of a software product. The advantage is that software quality manifests itself in the earliest phases of development and can be measured using static analyses. The disadvantage is that the measurement results of such static analyses must be manually interpreted and assessed to enable qualitative statements about the internal software quality. Therefore, this paper presents an approach that automates the assessment of the measurement results of static analyses. A benchmark-oriented assessment is presented, in which the measurement results of a software product under investigation are compared with the measurement results of reference products. Based on these comparisons, a so-called quality score is formulated, which indicates the extent to which the software product under investigation fulfills implicit requirements. The result of this work is a tool, which implements this approach. eingereicht von Philipp Stadler, BSc Universität Linz, Masterarbeit, 2021

Die Masterarbeit nimmt theoriegeleitet eine empirisch-analytische Untersuchung der direktdemokratischen Instrumente auf Bundes-, Landes- und Gemeindeebene in Österreich vor. Im Forschungsinteresse steht die Frage, inwieweit und unter welchen Bedingungen BürgerInnen mittels direktdemokratischer Verfahren erfolgreich in den Gesetzgebungsprozess eingreifen beziehungsweise als Vetospieler auftreten können, das heißt Gesetzesvorhaben oder -beschlüsse erfolgreich blockieren. Die Analyse zeigt einen eindeutigen Trend zur Weiterentwicklung der direkten Demokratie in den letzten Jahren: Ihre Instrumente werden quantitativ immer häufiger genutzt und qualitativ stetig verbessert. Während die Anzahl der UnterstützerInnen einer Initiative als Erfolgsbedingung ausgeschlossen werden kann, können zwei erfolgsverstärkende Muster für Instrumente der direkten Demokratie identifiziert werden. Erfolgreiche Verfahren weisen entweder (1) eine breit (über Parteigrenzen hinweg) aufgestellte Allianz an UnterstützerInnen auf und werden dabei oft als nur ein Element von größeren Kampagnen eingesetzt. Oder (2) das Verfahren wird zum richtigen Zeitpunkt im Gesetzgebungsprozess initiiert, zu dem der spezifische Sachverhalt bereits auf der politischen Tagesordnung steht, aber noch nicht fertig ausverhandelt ist das direktdemokratische Verfahren also in der Phase der Politikformulierung in den Policy-Zyklus eingreift. eingereicht von: Philipp Stadler Universität Linz, Masterarbeit, 2021

The most active and efficient catalysts for the electrochemical hydrogen evolution reaction (HER) rely on platinum, a fact that increases the cost of producing hydrogen and thereby limits the widespread adoption of this fuel. Here, a metalfree organic electrocatalyst that mimics the platinum surface by implementing a high work function and incorporating hydrogenaffine hydrogen bonds is introduced. These motifs, inspired from enzymology, are deployed here as selective reaction centres. It is shown that the ketoamine hydrogenbond motif enhances the ratedetermining step in proton reduction to molecular hydrogen. The ketoaminefunctionalized polymers reported herein evolve hydrogen at an overpotential of 190 mV. They share certain key properties with platinum: a similar work function and excellent electrochemical stability and chemical robustness. These properties allow the demonstration of one week of continuous HER operation without notable degradation nor delamination from the carrier electrode. Scaled continuousflow electrolysis is reported and 1 L net molecular hydrogen is produced within less than 9 h using 2.3 mg of polymer electrocatalyst. (VLID)5634597 Version of record

Electrocatalytic CO2-to-CO conversion represents one pathway to upgrade CO2 to a feedstock for both fuels and chemicals (CO, deployed in ensuing FischerTropsch or bioupgrading). It necessitates selective and energy-efficient electrocatalystsa requirement met today only using noble metals such as gold and silver. Here, we show that the two-dimensional sulfur planes in semimetallic titanium disulfide (TiS2) provide an earth-abundant alternative. In situ Fourier transform infrared mechanistic studies reveal that CO2 binds to conductive disulfide planes as intermediate monothiocarbonate. The sulfurCO2 intermediate state steers the reduction kinetics toward mainly CO. Using TiS2 thin films, we reach cathodic energy efficiencies up to 64% at 5 mA cm2. We conclude with directions for the further synthesis and study of semimetallic disulfides developing CO-selective electrocatalysts. (VLID)5874135 Accepted version

Conducting polymers represent an emerging class of conductors combining notable optoelectronic and thermoelectric properties; however, the electrical performance remains a limiting factor. This review provides an overview of the relevant parameters driving the rarely observed metal-insulator transition. Recent magnetotransport measurements provide clearer insight to study the proximity to the metallic state, i.e. the exact quantification of scattering and mobility. From that, one conclusion is the desired isotropic metallic phases depend on coherence and intermolecular radii. Version of record

Stable radicals in organic conjugated molecules are of great interest due to their magnetic signals and broad optical absorptions. In this paper, we report on naphthalene, benzoperylene, perylene, terrylene, and quaterrylene carboximides, reduced under controlled conditions, where stable metal-free solid salts of radical anions could be obtained forming darkly colored solutions with line-rich UV/Vis/NIR spectra and exhibiting special magnetic properties. The most bathochromic shift of the absorption maxima extend from 760 until 1700 nm. Persistent paramagnetic properties of the solids were observed and temperature-dependent susceptibilities are measured. Fonds zur Förderung der Wissenschaftlichen Forschung Z 222-N19 Version of record

Detection of enzymatic activities has been proposed as a rapid surrogate for the culture-based microbiological pollution monitoring of water resources. This paper presents the results of tests on four fully automated prototype instruments for the on-site monitoring of beta-d-glucuronidase (GLUC) activity. The tests were performed on sediment-laden stream water in the Hydrological Open Air Laboratory (HOAL) during the period of March 2014 to March 2015. The dominant source of faecal pollution in the stream was swine manure applied to the fields within the catchment. The experiments indicated that instrument pairs with the same construction design yielded highly consistent results (R2 = 0.96 and R2 = 0.94), whereas the results between different designs were less consistent (R2 = 0.71). Correlations between the GLUC activity measured on-site and culture-based Escherichia coli analyses over the entire study period yielded R2 = 0.52 and R2 = 0.47 for the two designs, respectively. The correlations tended to be higher at the event scale. The GLUC activity was less correlated with suspended sediment concentrations than with E. coli, which is interpreted in terms of indicator applicability and the time since manure application. The study shows that this rapid assay can yield consistent results over a long period of on-site operation in technically challenging habitats. Although the use of GLUC activity as a proxy for culture-based assays could not be proven for the observed habitat, the study results suggest that this biochemical indicator has high potential for implementation in early warning systems.

An important issue in construction of organic photovoltaic cells concerns the selective contacts. Here, especially the modification of the hole-extraction is challenging, as energy levels have to match the polymer's highest occupied molecular orbital (HOMO). We took the view to the mutual anode interface and we sought for a solution-based alternative for commonly used PEDOT:PSS – with an eye on improving the hole-extraction with an inorganic interlayer. We present copper iodide (CuI) as a versatile inorganic p-type semiconductor that meets the requirements for enhanced charge extraction in donor polymers. We applied two types of anthracene-containing PPE–PPV block–copolymers that recently gained attention as efficient active absorbers in bulk heterojunction photovoltaic cells. We report on the advantages using CuI as hole-selective contact and show an improvement of the power conversion efficiency in polymer-based solar cells.

Summary The bacterioplankton diversity in large rivers has thus far been under‐sampled despite the importance of streams and rivers as components of continental landscapes. Here, we present a comprehensive dataset detailing the bacterioplankton diversity along the midstream of the Danube River and its tributaries. Using 16S rRNA‐gene amplicon sequencing, our analysis revealed that bacterial richness and evenness gradually declined downriver in both the free‐living and particle‐associated bacterial communities. These shifts were also supported by beta diversity analysis, where the effects of tributaries were negligible in regards to the overall variation. In addition, the river was largely dominated by bacteria that are commonly observed in freshwaters. Dominated by the acI lineage, the freshwater SAR11 (LD12) and the P olynucleobacter group, typical freshwater taxa increased in proportion downriver and were accompanied by a decrease in soil and groundwater‐affiliated bacteria. Based on views of the meta‐community and River Continuum Concept, we interpret the observed taxonomic patterns and accompanying changes in alpha and beta diversity with the intention of laying the foundation for a unified concept for river bacterioplankton diversity.

Selective electrocatalysts are urgently needed for carbon dioxide (CO2) reduction to replace fossil fuels with renewable fuels, thereby closing the carbon cycle. To date, noble metals have achieved the best performance in energy yield and faradaic efficiency and have recently reached impressive electrical-to-chemical power conversion efficiencies. However, the scarcity of preciousmetalsmakes the search for scalable, metal-free, CO2 reduction reaction (CO2RR) catalysts all themore important. We report an all-organic, that is, metal-free, electrocatalyst that achieves impressive performance comparable to that of best-in-class Ag electrocatalysts. We hypothesized that polydopamine-a conjugated polymer whose structure incorporates hydrogen-bonded motifs found in enzymes-could offer the combination of efficient electrical conduction, together with rendered active catalytic sites, and potentially thereby enable CO2RR. Only by developing a vapor-phase polymerization of polydopamine were we able to combine the needed excellent conductivity with thin film-based processing. We achieve catalytic performance with geometric current densities of 18 mA cm(-2) at 0.21 V overpotential (-0.86 V versus normal hydrogen electrode) for the electrosynthesis of C-1 species (carbon monoxide and formate) with continuous 16-hour operation at >80% faradaic efficiency. Our catalyst exhibits lower overpotentials than state-of-the-art formate-selective metal electrocatalysts (for example, 0.5 V for Ag at 18mA cm(-1)). The results confirm the value of exploiting hydrogen-bonded sequences as effective catalytic centers for renewable and cost-efficient industrial CO2RR applications.

The current study reports the application of chalcopyrite semiconductor CuInS2 (CIS) nanofibers for the reduction of CO2 to CO with a remarkable Faradaic efficiency of 77 +/- 4%. Initially the synthesis of CuInS2 nanofibers was carried out by adaptable electrospinning technique. To reduce the imperfection in the crystalline fiber, polyacrylonitrile (PAN) was selected as template polymer. Afterward, the desired chemical structure of nanofibers was achieved through sulfurization process. Making continuous CuInS2 nanofibers on the cathode surface by the electrospinning method brings the advantages of being economical, environmentally safe, and versatile. The obtained nanofibers of well investigated size and diameter according to the SEM (scanning electron microscope) were used in electrochemical studies. An improvement of Faradaic efficiency was achieved with the catalytic active CuInS2 in nanofibrous structure as compared to the solution processed CuInS2. This underlines the important effect of the electrode fabrication on the catalytic performance. Being less contaminated as compared to solution processing, and having a well-defined composition and increased catalytically active area, the CuInS2 nanofiber electrodes prepared by the electrospinning technique show a 4 times higher Faradaic efficiency. Furthermore, in this study, attention was paid to the stability of the CuInS2 nanofiber electrodes. The electrochemical reduction of CO2 to CO by using CIS nanofibers coated onto FTO electrodes was carried out for 10 h in total. The observed current density of 0.22 mA cm(-2) and the stability of CIS nanofiber electrodes are found to be competitive with other heterogeneous electrocatalysts. Hence, we believe that the fabrication and application of nanofibrous materials through the electrospinning technique might be of interest for electrocatalytic studies in CO2 reduction.

Weak localization describes a metallic system, where due to the presence of disorder the electrical transport is governed by inelastic electron relaxation. Therefore the theory defines a threshold of spatial and of energetic disorder, at which a metal–insulator transition takes place. To achieve a metallic state in an inherently disordered system such as a conductive polymer, one has to overcome the threshold of localization. In this work we show that the effective suppression of disorder is possible in solution-processible poly(3,4-ethylenedioxythiophene)–poly(styrene sulfonate). We grow polymer films under optimized conditions allowing self-organization in solution. Interestingly, we find the requisite threshold, at which the system becomes finally metallic. We characterize the transition using a complementary morphology and magneto-electrical transport study and find coherent electron interactions, which emerge as soon as local order exceeds the macromolecular dimensions. These insights can be used for discrete improvement in the electrical performance, in particular for tailoring conductive polymers to alternative metal-like conductors. Fonds zur Förderung der Wissenschaftlichen Forschung Z222-N19 Version of record

During a campaign lasting from 27 October to 21 November 2010, sixty-one water samples were taken from the Kupa River, the catchment of which is about ten thousand square kilometres in size. Due to the fact that the upper tributaries of e.g. the ˇCabranka-, Dobra-, Korana-, Mrežnica- and Petrinjˇcica River comprise karstified Mesozoic carbonate formations, the hydrogeologic catchment of Kupa River extends the hydrologic one by far. The upper Kupa River is mainly charged by springs from big karst reservoirs in the Gorski Kotar mountain range, where a mean groundwater residence time of up to one year has to be considered. The rapid increase of discharge of these tributary rivers results from the rapid increase of discharge of karst wells after melting in springtime as well as from storm events. In general, the minimum mean discharge for all hydrographs in July reveals a dry summer season, with the maximum discharge in August/September resulting from an increase in precipitation. We interpret the d O-18 values of the ˇCabranka River (of about -8, 07h as signals from maritime precipitation in this karstified catchment area. The d O-18 value of upper Kupa River diminishes along its course from -8, 09h near Osilnica to -9, 06h west of Karlovac. After the inflow of tributaries south of Karlovac, the oxygen isotope ratio of Kupa River water reveals a significant change because the d O-18 values of the Dobra-, Korana- and Mrežnica River range from -10, 45h to -9, 58h . Due to the fact that the catchment of Dobra- and Korana River rises between 400 and 880 metres, we interpret the lower d O-18 values of river waters from recharge areas at those low mean altitudes as not caused by an altitude effect, but instead by precipitation out of more continental air masses. Our interpretation of stable isotope ratios in river waters is based on the relation between the weighted mean d O-18 and the altitude obtained from stations of the Global Network of Isotopes in Precipitation (GNIP), revealing an approximate vertical d O-18 gradient of -0, 30h per 100 m, as reported by Vreˇca et al. (2006). In addition, this stable isotope data for the GNIP station Zavižan predominantly indicates precipitation from the Adriatic coast, in contrary to the GNIP station Zagreb, the precipitation of which is more influenced by continental air masses. Due to the lack of local precipitation isotope data in the Kupa drainage basin it is not possible to directly analyse the modification of the isotopic signature and its temporal variation in river waters. To sum up, the isotopic composition of river waters in the Kupa Basin is controlled by two factors: the mean altitude of the recharge areas, and differences in the isotope composition of air moisture of more maritime or more continental influence. Along with use for hydrological investigations, the presented isotope data set can serve as a base line of isotope data for assessing future climate impacts within the Kupa Basin, such as temperature changes and change of precipitation distribution. Vreˇca, P., Broni´c, I. K., Horvatinˇci´c, N., Baresi´c, J. (2006): Isotopic characteristics of precipitation in Slovenia and Croatia: Comparison of continental and marine stations.- Journal of Hydrology, 330, 457-469.

For the very first time stable isotope data of river waters from Western Croatia are presented. During a campaign lasting from October 27 to November 21, 2010 sixty-seven water samples from sites along the three hundred kilometres long course of the Kupa River, and along selected tributary rivers of its catchment of about ten thousand square kilometres, respectively. We want to emphasize that hydrological conditions during the sampling period were influenced by heavy rain falls midst of October. Our interpretation of isotope ratios in river water is mainly based on the relation between weighted mean δ18O and the altitude obtained from stations of the Global Network of Isotopes in Precipitation (GNIP), revealing an approximate vertical δ18O gradient of 0, 30‰ per 100 m, as reported by Vreča et al. (2006). In addition, the δ18O data from the GNIP station Zavižan predominantly indicate precipitation from the Adriatic coast, in contrary to the GNIP station Zagreb, the precipitation of which is influenced by more continental air masses. The catchment of upper Kupa River in the Gorski Kotar rises up to 1500 metres above sea level (a.s.l.). Upper Kupa is mainly charged by springs from big karst reservoirs, in which a residence time of groundwater of up to one year has to be considered. We interpret the δ18O values of Čabranka River (about 8, 07‰) as signals from maritime precipitation in this karstified catchment area. The δ18O value of upper Kupa River diminishes along its course from 8, 09‰ near Osilnica to 9, 06‰ west of Karlovac. After the inflow of tributaries south of Karlovac the oxygen isotope ratio of Kupa River water reveals a significant change because δ18O values of Dobra-, Korana- and Mrežnica River are lower ( 10, 45‰ to 9, 58‰). The catchment of Dobra River and Korana River rises between 400 and 880 metres a.s.l. We interpret the lower δ18O values of river waters from the drainage basins at those low mean altitudes as basically not caused by an altitude effect, but caused by precipitation out of more continental air masses.

During a campaign lasting from October 27 to November 21, 2010 sixty-seven water samples were taken from sites along the three hundred kilometers long course of the Kupa River. We interpret the oxygen isotopic composition of the high part of the catchment of the upper Kupa River, comprising Čabranka River and its smaller tributaries down to Karlovac with higher Delta 18O-values of river waters, as predominantly influenced by maritime precipitation from the Kvarner Bay. The catchment of lower Kupa River and its tributaries, from Karlovac down to Sisak, and also the southern catchment of Dobra- and Korana River predominantly are influenced by precipitation out of more continental (humid) air masses. This more continental influence does not necessary imply precipitation out of drier air masses from the continental side but may also be the result of rainout influences on the isotopic composition of primary maritime air moisture. The high values of the deuterium excess of Kupa River waters (d= 11 to 17 promile) are similar to those reported by Vreča et al. (2006, Tab.2) for the station Zavižan - Mt. Velebit (d= 12 to 17 promile) and disagree with those of the station Zagreb-Grič (d= 7 to 10 promile). We therefore conclude that precipitation from the Adriatic side predominantly charges both karst water and river water of the Kupa catchment.

This work presents first complementary geochemical and stable isotope investigations of Risnjak Mountain karstic aquifer system in north-western Croatia. This aquifer is an important source of drinking water for both countries Croatia and Slovenia. The two main rivers, namely the Kupa River and the Rjecina River discharge the same mountain range, but belong to two different watersheds. Their springs are only 22 km apart, and located in scarcely populated areas. Kupa flows through limestones and dolomites in National Park Risnjak until it meets its largest tributary Cabranka. Rjecina flows first through flysch and carbonates before it enters the Adriatic Sea. At its lower course it flows through the densely populated town of Rijeka. For effective management of water resources the baseline data were collected. Sediment fraction

Graphical abstract Highlights ► The electrochemical p-doping of pentacene is reversible and stable shown by means of spectro-electrochemistry. ► Electrochemical p-doping can be directly applied to a pentacene-based transistor structure. ► Electrochemical contact doped transistors show significantly improved performances. ► A systematic analysis works out the reduction of contact barriers from the contact doping. ► The decrease of contact barriers is explained by the formation of a Mott–Schottky junction between metal and p-doped pentacene, By electrochemically p-doping pentacene in the vicinity of the source-drain electrodes in organic field effect transistors the injection barrier for holes is decreased. The focus of this work is put on the influence of the p-doping process on the transistor performance. Cyclic voltammetry performed on a pentacene based transistor exhibits a reversible p-doping response. This doped state is evoked at the transistor injection electrodes. An improvement is observed when comparing transistor characteristics before and after the doping process apparent by an improved transistor on-current. This effect is reflected in the analysis of the contact resistances of the devices.

A fully automated on-site device (SAMP-FIL) that enables water sampling with simultaneous filtration and effective cleaning procedures of the device's components was developed and field-tested. The SAMP-FIL was custom-built using commercially available components and was controlled by a RaspberryPi single-board computer operating open-source software. SAMP-FIL was designed for sample pre-treatment with minimal sample alteration to meet the requirements of on-site measurement devices that cannot handle coarse suspended solids within the measurement procedure or cycle. A highly effective cleaning procedure provides a fresh and minimally altered sample for the connected measurement device. The construction and programmed software facilitates the use of SAMP-FIL for different connected measurement devices. The SAMP-FIL sample pretreatment was tested for over one year for rapid and on-site enzymatic activity (beta-d-glucuronidase, GLUC) determination (BACTcontrol) in sediment-laden stream water. The formerly used proprietary sampling set-up was assumed to lead to significant damping of the measurement signal due to its susceptibility to clogging, debris accumulation and bio-film accumulation. The implementation of SAMP-FIL considerably increased the error-free running time and measurement accuracy of BACTcontrol devices. This paper describes how low-cost microcomputers, such as the RaspberryPi, can be used by operators to substantially improve established measuring systems via effective sampling devices. Furthermore, the results of this study highlight the importance of adequate sample pretreatment for the quality of on-site measurements.