Über die Wirkung der Korngrö$sZe von Stahl auf die Übergangstemperatur der Kerbschlagzähigkeit

Kerbschlagzähigkeitsuntersuchungen an drei unlegierten oder niedriglegierten Feinkornstählen unterschiedlicher Herstellung und Desoxydation und eine vergleichende Betrachtung an sieben, dem Schrifttum entnommenen unlegierten Baustählen. Zusammenhang zwischen der Übergangstemperatur (nach verschiedenen Festlegungen), der Korngrö$sZe und dem Mangangehalt. Einflu$sZ einer Wärmebehandlung auf die Korngrö$sZe und ihre Verknüpfung mit der Kerbschlagzähigkeit und dem Verformungsbruchanteil.     

An almost distribution-independent incremental Delaunay triangulation algorithm

This paper presents a new incremental insertion algorithm for constructing a Delaunay triangulation. Firstly, the nearest point is found in order to speed up the location of a triangle containing a currently inserted point. A hash table and 1–3 deterministic skip lists, combined with a walking strategy, are used for this task. The obtained algorithm is compared with the most popular Delaunay triangulation algorithms. The algorithm has the following attractive features: it is fast and practically independent of the distribution of input points, it is not memory demanding, and it is numerically stable and easy to implement.     

Internal oxidation of Ag–VC composites

The internal oxidation (IO) of Ag–VC composites containing 5 vol.% of carbide was examined at three oxidation temperatures (350, 400, 600 °C). Two mechanisms were observed due to the formation of double oxides with relatively low-melting points. At temperatures below the lowest eutectic point in situ, or diffusion less IO, was observed with the formation and growth of oxide layers surrounding the initial carbide. At temperatures above the eutectic point IO resulted in the formation of liquid oxide pools, which grew in size and developed into a network of oxides within the metal matrix. The kinetics confirmed the presence of two distinct mechanisms.     

Adaptive Response, Evidence of Cross-Resistance and Its Potential Clinical Use

Organisms and their cells are constantly exposed to environmental fluctuations. Among them are stressors, which can induce macromolecular damage that exceeds a set threshold, independent of the underlying cause. Stress responses are mechanisms used by organisms to adapt to and overcome stress stimuli. Different stressors or different intensities of stress trigger different cellular responses, namely induce cell repair mechanisms, induce cell responses that result in temporary adaptation to some stressors, induce autophagy or trigger cell death. Studies have reported life-prolonging effects of a wide variety of so-called stressors, such as oxidants, heat shock, some phytochemicals, ischemia, exercise and dietary energy restriction, hypergravity, etc. These stress responses, which result in enhanced defense and repair and even cross-resistance against multiple stressors, may have clinical use and will be discussed, while the emphasis will be on the effects/cross-effects of oxidants.     

Electrochemical and microstructural study of Cu-Al-Ni shape memory alloy

The corrosive behaviour of Cu-Al-Ni shape memory alloy in deaerated 0.5 M NaCl solution at 20 °C was studied by means of open circuit potential measurements, linear polarization, potentiodynamic polarization measurements, cyclic voltammetry and electrochemical impedance spectroscopy measurements. The electrode surface was examined by light microscope, SEM, XRD and EDX methods. The polarization measurements have shown that corrosive behaviour of Cu-Al-Ni alloy in NaCl solution was dominated by the Cu component. The results of impedance measurements at open circuit potential have shown that the overall impedance of the system increases with immersion time due to continuous growth of the passive film on the alloy surface. The XRD and EDX analysis showed the presence of copper, aluminium and nickel compounds, Cu-oxides and Cu-chlorides on alloy surface.     

Optimal conditions for determination of zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feed by micellar electrokinetic capillary chromatography

A separation technique for zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide in animal feedstuffs by micellar electrokinetic capillary chromatography (MEKC) was developed. The running buffer was 20 mmol l^-1 borate, 20 mmol l^-1 phosphate, pH 8.4, containing 20 mmol l^-1 sodium dodecylsulphate and 10% (v/v) methanol. MEKC was performed at 25°C; the applied voltage was 25 kV with a running pressure of 10 mbar. Simultaneous UV detection for all analytes was at 215 nm. The method was validated for specificity, accuracy, linearity, precision and robustness. It was shown to be specific, accurate (recoveries were 99.7 ± 0.3, 99.9 ± 0.9, 99.8 ± 1.0 and 99.5 ± 0.4, respectively, for oxytetracycline-, sulfacetamide-, polymyxin B- and zinc bacitracin-spiked samples of feed for cow, pigs, chicken and cattle), linear over the tested range (correlation coefficients ≥0.9987) and precise (RSDs below 1.8% for each analyte). The method was applied to determine zinc bacitracin, polymyxin B, oxytetracycline and sulfacetamide as additives in animal feed.     

A Survey of Parallel and Distributed Algorithms for the Steiner Tree Problem

Given a set of input points, the Steiner Tree Problem (STP) is to find a minimum-length tree that connects the input points, where it is possible to add new points to minimize the length of the tree. Solving the STP is of great importance since it is one of the fundamental problems in network design, very large scale integration routing, multicast routing, wire length estimation, computational biology, and many other areas. However, the STP is NP-hard, which shatters any hopes of finding a polynomial-time algorithm to solve the problem exactly. This is why the majority of research has looked at finding efficient heuristic algorithms. Additionally, many authors focused their work on utilizing the ever-increasing computational power and developed many parallel and distributed methods for solving the problem. In this way we are able to obtain better results in less time than ever before. Here, we present a survey of the parallel and distributed methods for solving the STP and discuss some of their applications.     

Modeling of containment atmosphere mixing and stratification experiment using a CFD approach

An experiment on containment atmosphere mixing and stratification, which was originally performed in the TOSQAN facility in Saclay (France), was simulated with the Computational Fluid Dynamics code CFX4.4. The TOSQAN facility consists of a large cylindrical vessel in which gases are injected. In the considered experiment, steam, air and helium were injected during different phases of the experiment, with steam condensing on some parts of the vessel walls. During certain phases, steady states were obtained when the steam condensation rate became equal to the steam injection rate, with all boundary conditions remaining constant. In the present work, three such intermediate steady states were simulated independently. The essential purpose was to reproduce the non-homogeneous structure of the vessel atmosphere, given that condensation is simulated in such a way to obtain the proper condensation rate. A two-dimensional axisymmetric model of the TOSQAN vessel for the CFX4.4 code was developed. The flow in the simulation domain was modeled as single-phase. Steam condensation on vessel walls was modeled as a sink of mass and energy. Calculated profiles of temperature, steam concentration, and velocity components are compared to experimental results and discussed. The comparison suggests that atmosphere mixing and stratification in an NPP containment at accident conditions could be successfully simulated using the proposed CFD approach.