[1] Sulfur and silicon are among the expected alloying light elements in planetary liquid iron cores. Structural properties of Fe-27 wt % S and Fe-17 wt % Si liquid alloys at high pressure and high temperature (0–5 GPa/1400–2300 K) are measured by synchrotron X-ray diffraction. Sulfur strongly modifies the local structure of liquid iron whereas silicon has only small structural effects. Fe-27 w...

Photoionization and recombination cross sections and rate coefficients are calculated for Li-like Fe XXIV and He-like Fe XXV using the Breit-Pauli R-matrix (BPRM) method. A complete set of total and level-specific parameters is obtained to enable X-ray photoionization and spectral modeling. The ab initio calculations for the unified (e + ion) recombination rate coefficients include both the non...

Both the Fe II UV emission in the 2000−3000 Å region (Fe II(UV)) and resonance emission line complex of Mg II at 2800 Å are prominent features in quasar spectra. The observed Fe II(UV)/Mg II emission ratios have been proposed as means to measure the buildup of the Fe abundance relative to that of the α-elements C, N, O, Ne and Mg as a function of redshift. The current observed ratios show large...

This work shows results of dynamic lumpedelement (LE) thermal modeling of power AlGaN/GaN HEMTs. A realistic 3D structure including top-side metals, GaN-Si thermal boundary resistance, die-attach, and source via hole is modeled using a finite-element (FE) tool, and the results are used to develop simplified LE dynamic thermal models. We show that the LE models can match the FE data with excelle...

Dielectronic recombination (DR) of Na-like Fe forming Mg-like Fe via excitation of a 2l core electron has been investigated. We find that configuration interaction (CI) between DR resonances with different captured electron principal quantum numbers n can lead to a significant reduction in resonance strengths for n ≥ 5. Including this form of CI accounts for most of the discrepancy between prev...

If O2 is available at circumneutral pH, Fe(2+) is rapidly oxidized to Fe(3+), which precipitates as FeO(OH). Neutrophilic iron oxidizing bacteria have evolved mechanisms to prevent self-encrustation in iron. Hitherto, no mechanism has been proposed for cyanobacteria from Fe(2+)-rich environments; these produce O2 but are seldom found encrusted in iron. We used two sets of illuminated reactors c...

In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates,...

This study focuses on development, characterization and validation of an artificial neural network (ANN) model for prediction of advanced oxidation of organics in water matrix. The different ANNs, based on multilayer perceptron (MLP) and radial basis function (RBF) methodologies, have been applied for modeling of the behavior of complex system; zero-valent iron activated persulfate oxidation (F...