Numerical simulations of compressible mixing layers with a discontinuous Galerkin method

Discontinuous Galerkin(DG) method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is developed for numerical simulations of both temporally and spatially developing mixing layers. For the temporally developing mixing layer,both the instantaneous fiow field and time evolution of momentum thickness agree very well with the previous results. Shocklets are observed at higher convective Mach numbers and the vortex paring manner is changed for high compressibility. For the spatially developing mixing layer,large-scale coherent structures and self-similar behavior for mean profiles are investigated. The instantaneous fiow field for a three-dimensional compressible mixing layer is also reported,which shows the development of largescale coherent structures in the streamwise direction. All numerical results suggest that the DG method is effective in performing accurate numerical simulations for compressible shear fiows.     

A general central limit theorem for strong mixing sequences

A central limit theorem for strong mixing sequences is given that applies to both non-stationary sequences and triangular array settings. The result improves on an earlier central limit theorem for this type of dependence given by Politis, Romano and Wolf in 1997.     

Linear seesaw model with T7 symmetry for neutrino mass and mixing

We propose a low-scale Standard Model extension with \begin{document}$T_7\times Z_4 \times Z_3\times Z_2$\end{document} symmetry that can successfully explain observed neutrino oscillation results within the \begin{document}$3 \sigma$\end{document} range. Small neutrino masses are obtained via the linear seesaw mechanism. Normal and inverted neutrino mass orderings are considered with three lepton mixing angles in their experimentally allowed \begin{document}$3\sigma$\end{document} ranges. The model provides a suitable correlation between the solar and reactor neutrino mixing angles, which is consistent with the \begin{document}${\rm{TM}}_2$\end{document} pattern. The prediction for the Dirac phase is \begin{document}$\delta_{\rm CP}\in (295.80, 330.0)^\circ$\end{document} for both normal and inverted orderings, including its experimentally maximum value, while those for the two Majorana phases are \begin{document}$\eta_1\in (349.60, 356.60)^\circ,\, \eta_2=0$\end{document} for normal ordering and \begin{document}$\eta_1\in (3.44, 10.37)^\circ, \, \eta_2=0$\end{document} for inverted ordering. In addition, the predictions for the effective neutrino masses are consistent with the present experimental bounds.     

Multi-component optical azimuthons of four-wave mixing

We report the multi-component optical azimuthons of four-wave mixing(FWM) composed of several modulated vortex beams, the so-called azimuthons, in V-type three-level and two-level atomic systems. We analyze the formation mechanisms of the FWM azimuthons theoretically and experimentally. In addition, we illustrate the interactions between the co-propagating azimuthon components. Finally, we also compare the stabilities of azimuthons in V-type three-level and two-level atomic systems.     

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In the situation of \rho-mixing dependent sequences, this paper studied the mean square error and the optimal bandwidth of distribution kernel estimator nu_{p,h} of VaR. And the optimal bandwidth minimized the mean square error. The density function of Laplace distribution is used in the calculation of bandwidth and we adopt the method of interpolation to compute specific value of bandwidth in this paper. According to the numerical simulations, the distribution kernel estimator is more accurate by comparing the performance of VaR distribution kernel estimation with a common order statistic. Finally, Shangzheng A-share index and Shenzheng B-share index are chosen for an empirical research, which concludes that the risk of the latter is significantly higher than that of the former.     

Radionuklide zur Prozeßanalyse in der Industrie

Unter Prozeβanalyse an Industrieanlagen wird die weitgehend umfassende Bestimmung von Prozeβvariablen wie Durchsatz, Stoffzusammensetzung, Verweilzeit, Mischverhalten, Phasengeschwindigkeiten in allen Prozeβstufen verstanden. Nach allgemein gültigen Hinweisen zur Durchführung von industriellen Tracerexperimenten warden als Beispiele Radionuklidprozeβanalysen der Brikettierung sowie der Caprolactamherstellung diskutiert. In beiden Fällen führten die Ergebnisse zu einer Erhöhung der Effektivität der Anlagen und zu einem bedeutenden volkswirtschaftlichen Nutzen. Die Qualität der Endprodukte wurde wesentlich verbessert.     

Eine Isotopenmethode zur Bestimmung der Effektivität von Anlagen zur Agglomerat-Herstellung

Die Mischungseffektivität von Dwight-Lloyd-Anlagen zur Herstellung von Eisen-Agglomerat wurde unter Verwendung von ¹⁴⁰La als Radiotracer untersucht. Das Markierungsverfahren fūr die Ausgangsmaterialien wird beschrieben.     

M(H) shape reconstruction using magnetic spectroscopy

Knowledge about the magnetization behavior M(H) is crucial for the use of magnetic materials in engineering applications. To date many systems exist that are able to measure the magnetization behavior, e.g. VSM, VCM, MOKE. In addition to their huge costs, complex and space-consuming measurement setup, large amount of preparatory work and restricted surface measurements are handicaps which restrict their field of application. Furthermore, the influence of additional physical quantities such as temperature, strain or pressure can only be investigated with great efforts. These influences are, however, of major importance in the development of magnetic sensor systems that are based on the change in magnetic properties.In this paper, a new measurement principle based on a frequency mixing technique is introduced for investigation of the shape of the magnetization curve of soft non-hysteretic magnetic materials. Based on the Taylor expansion of the magnetization curve and the spectral investigation of the inductively detected signal, a mathematical model for the reconstruction of M(H) is proposed. The model is both numerically and experimentally verified. It is shown that the magnetization curve of a nanocrystalline soft magnetic material used in this study can be reconstructed very accurately and the influence of an additional parameter, i.e. strain, can be investigated in detail as well.     

Slightly subcritical hypercube percolation

We study bond percolation on the hypercube {0,1}^m in the slightly subcritical regime where p = p_c(1 ? ε_m) and ε_m = o(1) but ε_m ? 2^?m/3 and study the clusters of largest volume and diameter. We establish that with high probability the largest component has cardinality , that the maximal diameter of all clusters is , and that the maximal mixing time of all clusters is . These results hold in different levels of generality, and in particular, some of the estimates hold for various classes of graphs such as high‐dimensional tori, expanders of high degree and girth, products of complete graphs, and infinite lattices in high dimensions.