Fluid‐structure coupling of linear elastic model with compressible flow models

Cavitation erosion is caused in solids exposed to strong pressure waves developing in an adjacent fluid field. The knowledge of the transient distribution of stresses in the solid is important to understand the cause of damaging by comparisons with breaking points of the material. The modeling of this problem requires the coupling of the models for the fluid and the solid. For this purpose, we use a strategy based on the solution of coupled Riemann problems that has been originally developed for the coupling of 2 fluids. This concept is exemplified for the coupling of a linear elastic structure with an ideal gas. The coupling procedure relies on the solution of a nonlinear equation. Existence and uniqueness of the solution is proven. The coupling conditions are validated by means of quasi‐1D problems for which an explicit solution can be determined. For a more realistic scenario, a 2D application is considered where in a compressible single fluid, a hot gas bubble at low pressure collapses in a cold gas at high pressure near an adjacent structure.     

High-precision sub-pixel interpolation in particle image velocimetry image processing

The task of image interpolation and re-sampling for particle image velocimetry (PIV) is investigated, which is used for window shifting with sub-pixel accuracy and image or window deformation. A new interpolation scheme based on a Gaussian filter is introduced and compared with commonly used and widely accepted interpolation techniques in terms of the achievable root mean square deviation of the displacement estimates.     

Homoconjugated ketones with extended unsaturation: Wavelength-selective,regioselective, diastereoselective,and enantiospecific photochemical transformations of methyl 7-oxospiro[5.5]undeca-1,3-and -2,4,-diene-2-carboxylate

The title molecules were shown to photorearrange with remarkable selectivity. Wavelength variation steers the rearrangement modes, of which the [1,2]-acyl shift was found to be largely regioselective, diastereoselective, and enantiospecific. Chemical intercorrelation of products and mechanistic studies were carried out all along. The potential significance of these photochemical processes in selective synthetic schemes is discussed.     

Recoil spectrometry: Ion accelerator based elemental characterisation of surface layers

Recoil Spectrometry covers a group of techniques that are very similar to the well known Rutherford backscattering Spectrometry technique, but with the important difference that one measures the recoiling target atom rather than the projectile ion. This makes it possible to determine both the identity of the recoil and its depth of origin from its energy and velocity, using a suitable detector system. The incident ion is typically high-energy (30–100MeV)³⁵C1,⁸¹Br or¹²⁷I. Low concentrations of light elements such as C, O and N can be profiled in a heavy matrix such as Fe or GaAs. Here we present an overview of mass and energy dispersive recoil Spectrometry and illustrate its successful use in some typical applications.     

CHROMOPHORE ROTATION IN 124-kD ALTON A vena sativa PHYTOCHROME AS MEASURED BY LIGHT-INDUCED CHANGES IN LINEAR DICHROISM

Abstract— From light-induced changes in linear dichroism, we have calculated the rotation of the long-wavelength-absorbing transition moment that occurs during phototransformation of 124-kilodalton Avena sativa phytochrome. Phytochrome was purified to homogeneity and immobilized onto Sepharose beads covalently coated with antibodies against A. sativa phytochrome. Changes in linear dichroism were induced by plane-polarized red or far-red light and measured by the absorbance differences at 660 and 730 nm using a dual-wavelength spectrophotometer equipped with polarizing filters in the measuring beams. From such measurements, we calculate a rotation angle of 31^o (or 149^o) during photoconversion of Pr to Pfr and 30^o (or 150^o) during photoconversion of Pfr to Pr. These values are similar to the value of 32^o (or 148^o) reported earlier for the rotation of the transition moment of "large" A. sativa phytochrome (∽ 120 kilodalton) isolated under conditions that did not preclude post homogenization proteolysis of the 124 kilodalton molecule.     

Evidence for N2N3N45 super coster kronig processes in metallic Nb,Mo, Ru and Rh

The 4p photoelectron spectra of metallic Nb, Mo, Ru and Rh have been recorded. By use of a deconvolution procedure it is shown that the 4p_{$\text{1}\text{2}$} spin-orbit component has a linewidth which significantly exceeds that of the 4p_{$\text{3}\text{2}$} component. This suggests that N₂N₃N₄₅ super Coster Kronig processes give a considerable contribution to the decay rata of the 4p_{$\text{1}\text{2}$} hole state.