Möglichkeiten zur Vorhersage unerwünschter Phasen in technischen hochwarmfesten Nickellegierungen durch die mittlere Elektronenleerstellenzahl der Schmelzenzusammensetzung

Die Elektronenverteilung als Voraussetzung für die Bildung der σ-Phase. Ableitung des Begriffs der Elektronenleerstellenzahl N_v für die reinen Übergangsmetalle und der mittleren Elektronenleerstellenzahl N?_v für Mischkristalle. Abgrenzung des Existenzbereiches der σ-Phase durch Linien gleichbleibender N?_v-Werte, Annahmen bezüglich der chemischen Zusammensetzung der vorangehenden Ausscheidungen und der Restmatrix zur Berechnung der N?_v-Werte nach acht verschiedenen Rechenverfahren. Einführung legierungsspezifischer Löslichkeitszahlen für die Legierungsbestandteile und Hinweis auf legierungsspezifische N?_v-Grenzwerte.     

Defekt des Herzbeutels bei einem jungen Reh

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Parametric optimization of intra‐ and inter‐layer strengths in parts produced by extrusion‐based additive manufacturing of poly(lactic acid)

Parts produced by extrusion‐based additive manufacturing experience the disadvantage of consisting of many weld‐lines, which consequently downgrade their mechanical properties. This work aims at maximizing the strength of printed parts by considering and improving the intra‐ and inter‐layer cohesion between adjacent strands. Therefore, printed poly(lactic acid) specimens were characterized by means of a particular tensile test setup, and the inter‐layer cohesion of printed specimens was evaluated by means of the double cantilever beam test. A detailed parametric statistical evaluation, which included printing temperatures, layer thicknesses, and layer‐designs, was complemented by the material's viscosity data and the analysis of the specimens' fracture surfaces and cross‐sections. An optimal layer‐design was found to be a key parameter in the optimization of strength with regard to different loading directions. Additionally, the maximization of the cohesion leads to a tremendous improvement in the mechanical performance of the printed parts, resulting in strengths of roughly 90% of those of compression‐molded parts. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45401.     

The Role of Intuition and Deliberation for Exploration and Exploitation Success

Advances in social and cognitive psychology and related fields have drawn attention to the role of intuition in organizational decision making. In this study we link intuitive and deliberate decision‐making styles to the success of exploration and exploitation activities, which are understood as two qualitatively opposing strategies that organizations can adopt. We provide empirical evidence that the two opposing strategies are linked to two opposing styles of decision making – intuitive and deliberate. In doing so, we draw on data which we received from 140 entrepreneurs and managing partners of Austrian companies and show that exploration is strongly related to intuitive decision making whereas exploitation draws on both intuitive and deliberate decision making. Based on our findings, we stress the complementarity of the two decision‐making styles, and point out that particularly in the light of the fast‐changing premises in which organizations have to manoeuvre today, decision makers are well advised to use both decision‐making styles to their best benefit.     

A novel protocol to design TiO2-Fe2O3 hybrids with effective charge separation efficiency for improved photocatalysis

TiO₂-based heterogeneous photocatalysis has been widely considered as a promising technique for decontamination of water. Herein the hybrid of TiO₂ nanocrystals decorated Fe₂O₃ nanoparticles was successfully synthesized via a mild hydrothermal method, derived from favorable titanium glycolate and water-soluble Fe^II salt precursors. The composition and structure of the as-synthesized TiO₂-Fe₂O₃ hybrids were characterized by Powder X-ray diffraction (XRD), EDX mapping, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). The photocatalytic activity was evaluated by the decomposition of Rhodamine B in an aqueous solution under visible-light (λ > 420 nm). The results show that the TiO₂-Fe₂O₃ nanocomposite exhibits superior photocatalytic capability to the bare ones upon Rhodamine B degradation, owing to promoted photo-induced electrons and holes separation and migration on the basis of photoluminescence spectra, photocurrent measurements, and electrochemical impedance (EIS) spectroscopy.     

Membrane Fluidity Changes,A Basic Mechanism of Interaction of Gravity with Cells?

All life on earth has been established under conditions of stable gravity of 1g. Nevertheless, in numerous experiments the direct gravity dependence of biological processes has been shown on all levels of organization, from single molecules to humans. According to the underlying mechanisms a variety of questions, especially about gravity sensation of single cells without specialized organelles or structures for gravity sensing is being still open. Biological cell membranes are complex structures containing mainly lipids and proteins. Functional aspects of such membranes are usually attributed to membrane integral proteins. This is also correct for the gravity dependence of cells and organisms which is well accepted since long for a wide range of biological systems. However, it is as well established that parameters of the lipid matrix are directly modifying the function of proteins. Thus, the question must be asked, whether, and how far plain lipid membranes are affected by gravity directly. In principle it can be said that up to recently no real basic mechanism for gravity perception in single cells has been presented or verified. However, it now has been shown that as a basic membrane parameter, membrane fluidity, is significantly dependent on gravity. This finding might deliver a real basic mechanism for gravity perception of living organisms on all scales. In this review we summarize older and more recent results to demonstrate that the finding of membrane fluidity being gravity dependent is consistent with a variety of published laboratory experiments. We additionally point out to the consequences of these recent results for research in the field life science under space condition.     

Calibration by optimization without using derivatives

Applications in engineering frequently require the adjustment of certain parameters. While the mathematical laws that determine these parameters often are well understood, due to time limitations in every day industrial life, it is typically not feasible to derive an explicit computational procedure for adjusting the parameters based on some given measurement data. This paper aims at showing that in such situations, direct optimization offers a very simple approach that can be of great help. More precisely, we present a numerical implementation for the local minimization of a smooth function \(f:{\mathbb R}^n\rightarrow {\mathbb R}\) subject to upper and lower bounds without relying on the knowledge of the derivative of f. In contrast to other direct optimization approaches the algorithm assumes that the function evaluations are fairly cheap and that the rounding errors associated with the function evaluations are small. As an illustration, this algorithm is applied to approximate the solution of a calibration problem arising from an engineering application. The algorithm uses a Quasi-Newton trust region approach adjusting the trust region radius with a line search. The line search is based on a spline function which minimizes a weighted least squares sum of the jumps in its third derivative. The approximate gradients used in the Quasi-Newton approach are computed by central finite differences. A new randomized basis approach is considered to generate finite difference approximations of the gradient which also allow for a curvature correction of the Hessian in addition to the Quasi-Newton update. These concepts are combined with an active set strategy. The implementation is public domain; numerical experiments indicate that the algorithm is well suitable for the calibration problem of measuring instruments that prompted this research. Further preliminary numerical results suggest that an approximate local minimizer of a smooth non-convex function f depending on \(n\le 300 \) variables can be computed with a number of iterations that grows moderately with n.     

Characteristics improvement of top‐gate self‐aligned amorphous indium gallium zinc oxide thin‐film transistors using a dual‐gate control

In this work, we have reported dual‐gate amorphous indium gallium zinc oxide thin‐film transistors (a‐IGZO TFTs), where a top‐gate self‐aligned TFTs has a secondary bottom gate and the TFT integration comprises only five mask steps. The electrical characteristics of a‐IGZO TFTs under different gate control are compared. With the enhanced control of the channel with two gates connected together, parameters such as on current (I_ON), sub‐threshold slope (SS^?1), output resistance, and bias‐stress instabilities are improved in comparison with single‐gate control self‐aligned a‐IGZO TFTs. We have also investigated the applicability of the dual‐gate a‐IGZO TFTs in logic circuitry such as 19‐stage ring oscillators.