Oxygen plasma flow properties deduced from laser-induced fluorescence and probe measurements

Estimation of the local dissociation degree and the local mass-specific enthalpy of a pure oxygen plasma flow determined mainly from laser-induced fluorescence measurements are reported. Measurements have been conducted for several generator parameters in an inductively heated plasma wind tunnel. Additional probe measurements of total pressure together with the deduced translational temperature are used to estimate the local mass-specific enthalpy. For a reference condition, full dissociation has been measured. The measured translational temperature of atomic oxygen for this condition is T = 3500 K. Subsequently, the local mass-specific enthalpy has been derived using these local density and temperature measurements. For the reference condition the estimated value of h = 27 MJ/kg is in good agreement with the probe measurements and results from diode laser absorption spectroscopy.     

Switchable windows with tungsten oxide

Tungsten oxide can change its colour reversibly upon electron injection. It can be produced by sputtering, evaporation, chemical vapour deposition or other processes. In addition to its high colouration efficiency and fast reaction kinetics, the redox potential of the electron injection is low enough to allow various switchable systems, such as electrochromic, gasochromic, photoelectrochromic or photochromic glazing. In this paper, electrochromic devices with a redox electrolyte are introduced. This is related to the photoelectrochromic device, which is an electrochromic device with redox electrolyte and an additional dye-sensitised layer of TiO₂, which generates the energy for the colouration of the device by sunlight. The photochromic device is in principal a photoelectrochromic device, where the catalytic layer for the reaction of the redox electrolyte is in direct contact with the electrochromic layer. In gasochromic devices, tungsten oxide reacts with diluted hydrogen and oxygen gases. This paper aims to give an overview of these different approaches.     

Numerical study on the prediction of microstructure parameters by multi-scale modeling of directional solidification of binary aluminum–silicon alloys

In order to create a model to predict microstructural quantities like grain size, primary and secondary dendrite arm spacing a multi-phase and multi-scale model based on the work of Wang and Beckermann [C. Wang, C. Beckermann, Metallurgical and Materials Transactions A 27A (1996) 2754–2764] was combined with a front tracking technique [A. Wu, A. Ludwig, in: C.-A. Gandin, M. Bellet (Eds.), Modeling of Casting, Welding, and Advanced Solidification Processes – XI, TMS, 2006, pp. 291–298], micro-models for nucleation [M. Rappaz, P. Thevoz, Acta Metallurgica 35 (7) (1987) 1487–1497], primary [J. Hunt, S.-Z. Lu, Metallurgical and Materials Transactions A 27A (1996) 611–623], secondary [W. Kurz, D. Fisher, Fundamentals of Solidification, Trans Tech Publication, 1986, ISBN 0-87849-522-3] dendrite arm spacing and a control volume based finite element solver for axial-symmetric problems. As most of the micro-models are just valid for pure diffusive conditions, the model just takes into account macroscopic diffusion in the melt and thus neglects the influence of melt flow. The new software was used for a comprehensive comparison to several test cases. The validation includes investigation of the correlation of calculated and measured grain size distributions for inoculated alloys. Experimental and numerical data for the primary and secondary dendrite arm spacing for steady state and transient directional solidification were compared in a second step. A good correlation is found for all test cases.     

Orientation-dependent ionization energies and interface dipoles in ordered molecular assemblies

Although an isolated individual molecule clearly has only one ionization potential, multiple values are found for molecules in ordered assemblies. Photoelectron spectroscopy of archetypical pi-conjugated organic compounds on metal substrates combined with first-principles calculations and electrostatic modelling reveal the existence of a surface dipole built into molecular layers. Conceptually different from the surface dipole at metal surfaces, its origin lies in details of the molecular electronic structure and its magnitude depends on the orientation of molecules relative to the surface of an ordered assembly. Suitable pre-patterning of substrates to induce specific molecular orientations in subsequently grown films thus permits adjusting the ionization potential of one molecular species over up to 0.6 eV via control over monolayer morphology. In addition to providing in-depth understanding of this phenomenon, our study offers design guidelines for improved organic-organic heterojunctions, hole- or electron-blocking layers and reduced barriers for charge-carrier injection in organic electronic devices.     

Screening for New Inhibitors of Glycine Transporter 1 and 2 by Means of MS Binding Assays

A straightforward screening of a compound library comprising 2439 substances for the identification of new inhibitors for the neurotransmitter transporters GlyT1 and GlyT2 is described. Screening and full-scale competition experiments were performed using recently developed GlyT1 and GlyT2 MS Binding Assays. That way for both targets, GlyT1 and GlyT2, ligands were identified, which exhibited affinities (pK_i values) in the low micromolar to sub-micromolar range. The majority of these binders exhibit new chemical scaffolds in the class of GlyT1 and GlyT2 inhibitors, which could be of interest for the development of new ligands with improved affinities for the target proteins. Additionally, compounds with excellent fluorescent properties were found for GlyT2, which renders them promising compounds for future fluorescence-based techniques. All in all, this study demonstrates that MS Binding Assays represent a powerful technology platform also well suited for the screening of compound libraries in a highly reliable and effective manner.     

Closure of German Hard Coal Mines: Effects and Legal Aspects of Mine Flooding

Following the closure of the last hard coal mines in Germany, pumping is no longer necessary. However, the resulting rise of mine water can affect the environment. Laws have been enacted at the European and national level to protect properties. Within the framework of the approval procedure, it must be determined whether the cessation of pumping may cause unacceptable effects, including water pollution. With regard to water protection, the European Union has issued the Water Framework and Groundwater Directives, which have been implemented into German national law. These contain the prohibition of deterioration and the requirement for improvement, with the aim of maintaining or achieving good ecological and chemical status. However, before the target mine water level is reached, the water does not need to comply, since although the pumps are switched off, no mine water is being discharged. This also rules out permit requirements, which only go into effect when the target mine water level has been reached and mine water is discharging. Obviously, however, detailed planning before then is necessary.

     

The role of lake size and local phenomena for monitoring ground-fast lake ice

In this study, we assess the effect of the lake size on the accuracy of a threshold-based classification of ground-fast and floating lake ice from Sentinel-1 Synthetic Aperture Radar (SAR) imagery. For that purpose, two new methods (flood-fill and watershed method) are introduced and the results between the three classification approaches are compared regarding different lake size classes for a study area covering most of the Yamal Peninsula in Western Siberia. The focus is on April, the stage of maximum lake ice thickness, for the years 2016 and 2017. The results indicate that the largest lakes are likely most prone to errors by the threshold classification. The newly introduced methods seem to improve classification results. The results also show differences in fractions of ground-fast lake ice between 2016 and 2017, which might reflect differences in temperatures between the winters with severe impact on wildlife and freshwater fish resources in the region. Patterns of low backscatter responsible for the classification errors in the centre of the lakes were investigated and compared to the optical Sentinel-2 imagery of late-winter. Strong similarities between some patterns in the optical and SAR data were identified. They might be zones of thin ice, but further research is required for clarification of this phenomenon and its causes.     

State‐of‐the‐Art Analytical Methods for Assessing Dynamic Bonding Soft Matter Materials

Dynamic bonding materials are of high interest in a variety of fields in material science. The reversible nature of certain reaction classes is frequently employed for introducing key material properties such as the capability to self‐heal. In addition to the synthetic effort required for designing such materials, their analysis is a highly complex—yet important—endeavor. Herein, we critically review the current state of the art analytical methods and their application in the context of reversible bonding on demand soft matter material characterization for an in‐depth performance assessment. The main analytical focus lies on the characterization at the molecular level.     

Investigations of MX and γ′/γ″ precipitates in the nickel-based superalloy 718 produced by electron beam melting

Samples with a composition similar to the nickel-based superalloy Inconel alloy 718 were produced by electron beam melting of prealloyed powder and investigated with respect to type and composition of the strengthening precipitates. The matrix consists of γ grains orientated in nearly the same direction, almost like a single crystal. Coarse precipitates (<2 μm), mostly of the (Ti,Nb)(C,N,B) type with B1 structure, are aligned along the growth direction. TEM and APFIM investigations of the γ matrix revealed very fine γ″ precipitates of around 5–10 nm in size. Additionally, at small angle grain boundaries, coarser γ″ precipitates of 50–100 nm in size have been observed. The 0 01 γ//0 0 1 γ″ and {1 0 0} γ//{1 0 0} γ″ orientation relationship between γ and γ″, known from literature [M. Sundararaman, P. Mukhopadhyay, Mater. Charact. 31 (1993) 191–196], was confirmed. Some γ′ precipitates of 2–5 nm in size were observed by means of FIM.