Solvent-free chemical functionalization of hydrogen-terminated boron-doped diamond electrodes with diazonium salts in ionic liquids

This paper reports on green chemical functionalization of hydrogen-terminated boron-doped diamond (BDD) surfaces with aryldiazonium salts in the presence of ionic liquids. The reaction takes place at room temperature in air without any external bias in either hydrophobic (1-butyl-3-methylimidazolium hexafluorophosphate) or hydrophilic (1-butyl-3-methylimidazolium methyl sulfate) ionic liquids. The resulting surfaces were characterized using X-ray photoelectron spectroscopy and electrochemical measurements.     

Effective elastic properties and residual stresses in directionally solidified eutectic Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/YAG/ZrO<Subscript>2</Subscript> ceramics estimated by finite element analysis

Effective elastic properties and residual stresses were assessed in directionally solidified ternary eutectic ceramic, Al₂O₃/YAG/ZrO₂, by finite element analyses. A 3D finite element model was generated from a CT scan, representative of the microstructure and with a similar volume fraction. Effective elastic properties were calculated by numerical homogenisation. They highlight a quasi-isotropic behaviour of the ternary eutectic ceramics. Despite the difficulties to measure the strain, the dispersion observed in the results and the limited reliability of the materials properties, the results constitute a step towards a better understanding of the material behaviour. Thermal residual stresses induced by the manufacturing were also evaluated. Tensile residual stresses in yttria-stabilised zirconia and compressive residual stresses in YAG and alumina were highlighted. This evaluation also shed light on the influence of the phase morphology in the microstructure. Indeed, the computed spatial distribution of the residual stresses showed that they are different from one position to another due to the variation in phase morphology and also to material properties variability. Therefore, it is important when numerically assessing the thermomechanical properties to take into account the microstructure morphology as well as the variability of material properties.     

Science and technology in the region: The output of regional science and technology, its strengths and its leading institutions

Summary We operationalize scientific output in a region by means of the number of articles (as in the SciSearch database) per year and technology output by means of the number of patent applications (as in the database of the European Patent Office) per priority year. All informetric analyses were done using the DIALOG online-system. The main research questions are the following: Which scientific and technological fields or topics are most influent within a region and which institutions or companies are mainly publishing articles or holding patents? Do the distributions of regional science and technology fields and of publishing institutions follow the well-known informetric function? Are there - as it is expected - only few fields and few institutions which dominate the region? Is there a connection between the economic power of a region and the regional publication and patent output? Examples studied in detail are seven German regions: Aachen, D&uuml;sseldorf, Hamburg, K&ouml;ln (Cologne), Leipzig - Halle - Dessau, M&uuml;nchen (Munich), and Stuttgart. Three different indicators were used, science and technology attraction of a region (number of scientific articles and patents), science and technology intensity (articles and patents per 1,000 inhabitants), and science and technology density (articles and patents per 1 billion EURO gross value added). Top region concerning both attraction and intensity is Munich, concerning density it is Aachen.     

Retracted papers by Iranian authors: causes,journals, time lags,affiliations, collaborations

Scientometrics - This study aims to analyze 343 retraction notices indexed in the Scopus database, published in 2001–2019, related to scientific articles (co-)written by at least one author...     

The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition

Journal of Materials Science - The superionic α???β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and...     

Characterization of catalysts obtained from rapidly quenched alloy precursors by electrochemical/chemical processes of material degradation—selected examples

Rapidly quenched amorphous alloys—containing metallic or metalloid elements—are precursors for selective catalysts of many technically important reactions. To increase their activity, various methods of material degradation occurring at the surface and in the bulk of the rapidly quenched alloys have been used for promoting the catalytic performance of such materials. The modifications of the structure, composition, and morphology of the substrate proved to be efficient in transforming inactive metal alloy precursors into active and selective catalysts for hydrogenation, and dehydrogenation of organic compounds, as well as for other processes like steam reforming of methanol. This article presents several examples of characterization of such catalysts and discusses their selectivity and activity in a connection with physical and chemical properties of their surfaces. Moreover, it is shown that scanning electron microscopy, Auger electron spectroscopy, scanning Auger microscopy, and energy dispersive spectrometry allowed the local changes occurring during the activation process to be identified and their implications for catalytic function to be considered.     

A two-scale approach for trabecular bone microstructure modeling based on computational homogenization procedure

In this paper the numerical implementation of two-scale modelling of bone microstructure is presented. The study is a part of long-term project on bone remodelling which drives bone microstructure change based directly on trabeculae surface energy. The proposed approach is based on a first-order computational homogenization technique. The coincidence of macro- and micro-model kinematics is done with the use of uniform displacement and traction boundary conditions. The computational homogenization procedure is driven by a self-prepared manager which is coded in Python. The computation on real bone structure (a piece of female Wistar rat bone) is performed as well.