Numerical analysis of dipole sound source around high speed trains

As the maximum speed of high speed trains increases, the effect of aeroacoustic noise on the sound level on the ground becomes increasingly important. In this paper, the distribution of dipole sound sources at the bogie section of high speed trains is predicted numerically. The three-dimensional unsteady flow around a train is solved by the large eddy simulation technique. The time history of vortices shows that unstable shear layer separation at the leading edge of the bogie section sheds vortices periodically. These vortices travel downstream while growing to finally impinge upon the trailing edge of the section. The wavelength of sound produced by these vortices is large compared to the representative length of the bogie section, so that the source region can be regarded as acoustically compact. Thus a compact Green's function adapted to the shape can be used to determine the sound. By coupling the instantaneous flow properties with the compact Green's function, the distribution of dipole sources is obtained. The results reveal a strong dipole source at the trailing edge of the bogie section where the shape changes greatly and the variation of flow with time is also great. On the other hand, the bottom of the bogie section where the shape does not change, or the leading edge and boundary layer where the variation of flow with time is small, cannot generate a strong dipole source.     

Light attenuation in a semitransparent foam sheet-Thickness measurement for industrial use

An optical method for measuring the thickness of heterogeneous materials has been studied. The method is based on the light attenuation theory. A complete system has been constructed in order to demonstrate the applicability of the present method for industrial use. The experimental set-up consists of semiconductor lasers, focusing lenses, photo-diodes serving as a power meter and a personal computer with an A/D converter for data acquisition. Averaging of numerous measurements is required in the present method because the heterogeneous cell structure of the foam material yields large fluctuations in transmitted light levels. The fluctuations can be reduced to below 1% of the transmitted light power by 80 times averaging. The error of the measurement is considered to be a few tens of micrometers in thickness. The present system is capable of sampling data at a rate of 400 Hz and has been successfully applied to a manufacturing process.     

Quantum Mechanics of the Composite System and Its Subsystems

We revisit the EPR problem and make clear what is a correct comprehension of its problem. When one applies the quantum mechanics correctly, it will be shown that there is no paradox. According to these lines of thought, a quantum teleportation scheme without resort to the von Neumann projection postulate is presented.     

Finite solvable groups whose $$\mathfrak{F}$$ -hypercenter contains all minimal subgroups

Archiv der Mathematik -     

Krafft temperature and enthalpy of solution of<Emphasis Type="Italic"> N</Emphasis>-acyl amino acid surfactants and their racemic modifications: effect of the counter ion

The Krafft temperatures and enthalpies of solution of N-hexadecanoyl alaninate and valinate, and N-tetradecanoyl phenylalaninate were obtained from differential scanning calorimetry. The Krafft temperature of N-acyl amino acid surfactant increased with decreasing size of the counter ion, with some exceptions. The enthalpy of solution was endothermic and increased with decreasing size of the counter ion except for the cases of lithium salt. The results showed that the L-L interaction in the solid state of N-hexadecanoyl amino acid surfactant salt was superior to the D-L interaction for both the alanine and valine systems when the counter ion size increased. However, the D-L interaction was still advantageous for the phenylalanine system with Cs⁺ as a counter ion. Both Fourier transform infrared spectroscopy studies and theoretical calculations suggested that the difference in magnitudes of the interactions between peptide and counter ion was a dominant factor for the chiral effect.     

Sigmasigma* transition in anti,cisoid alternating oligosilanes: clear-cut evidence for suppression of conjugation effect by a cisoid turn

On the basis of the UV absorption spectra of the anti,cisoid alternating oligosilanes, the first experimental clear-cut evidence was presented for the generally accepted idea that the sigma conjugation in polysilanes does not effectively extend through a tetrasilane fragment with a small dihedral angle such as a cisoid turn.     

Development and validation of a high-precision capillary electrophoresis method for main component assay of ragaglitazar

The ability of a developed capillary electrophoresis (CE) method for fast, efficient and reliable main component assay of ragaglitazar [NNC 61-0029/DRF(-)2725] has been demonstrated through documentation of the analytical performance and the results of a successful validation. The fast analysis time of around 1.2 min ensures a high analytical capacity, and the validation results show that the CE method is robust and gives reliable and precise results. The results from the validation of the CE method meet the acceptance criteria that are normally set for other main component assays such as high-performance liquid chromatography assays.     

DFT studies of ESR parameters for N?O centered radicals,N‐alkoxyaminyl and aminoxyl radicals

Theoretical calculations of ESR parameters for aminoxyl radicals have been widely studied using the density functional theory (DFT) calculations. However, the isomer N‐alkoxyaminyl radicals have been limitedly studied. With the use of experimental data for 46 N‐alkoxyaminyl and 38 aminoxyl radicals, the isotropic ¹⁴N hyperfine coupling constants (a_N) and g‐factors have been theoretically estimated by several DFT calculations. The best calculation scheme of a_N for N‐alkoxyaminyl radicals was PCM/B3LYP/6‐31 + + G(d,p) (R² = 0.9519, MAE = 0.034 mT), and that for aminoxyl radicals was PCM/BHandHLYP/6‐31 + + G(3df,3pd) (R² = 0.9336, MAE = 0.057 mT). For aminoxyl radicals, the solvation models in calculations enhanced the accuracy of reproducibility. In contrast, for N‐alkoxyaminyl radicals the calculations with solvation models provided no improvement. The differences in the best functionals between two types of radicals were thought to come from the contribution ratios of neutral and dipolar canonical structures in resonance forms. The a_N for N‐alkoxyaminyl radicals that were stabilized by small contribution of dipolar canonical structures could be precisely reproduced by B3LYP with only 20% HF exact exchange. In contrast, the a_N for aminoxyl radicals stabilized by large contribution of dipolar canonical structures was well reproduced by BHandHLYP with 50% HF exchange. The best calculation scheme of g‐factors was IEFPCM/B3LYP/6‐31 + G(d,p) (R² = 0.9767, MAE = 0.0001) for not only aminoxyl but also N‐alkoxyaminyl radicals. Copyright © 2011 John Wiley & Sons, Ltd.