Various electrochemical approaches, including potentiodynamic polarization, open circuit potential evolution and electrochemical impedance spectroscopy (EIS), are employed to investigate the degradation behavior of biomedical magnesium alloy under the influence of aggressive ions, such as chloride, phosphate, carbonate and sulfate, in a physiological environment. The synergetic effects and mutu...

Hydrothermal venting and the formation of carbonate chimneys in the Lost City hydrothermal field (LCHF) are driven predominantly by serpentinization reactions and cooling of mantle rocks, resulting in a highly reducing, high-pH environment with abundant dissolved hydrogen and methane. Phylogenetic and terminal restriction fragment length polymorphism analyses of 16S rRNA genes in fluids and car...

The general purpose of this study is to develop both efficient and equitable freeway ramp control strategies. Measures of efficiency and equity for ramp meters are defined and applied to data collected in the Twin Cities ramp metering shut-off experiment. A trade-off between efficiency and equity is evident from the results of data analysis. A new time-dependent optimization program for the glo...

A major role of lobster integument is protection from microbes. Calcite and amorphous calcium carbonate are the most abundant and most acid vulnerable of the cuticle minerals. We propose that calcite is invested in neutralizing an acidifying environment modulated by the epicuticle. A minor cuticle component is carbonate apatite (CAP), proposed to play critical roles in the integument!s structur...

Marine microbialites serve as robust seawater rare earth element and yttrium (REE+Y) proxies through many intervals of Earth history, but questions remain about the partitioning of REEs into different coeval carbonate phases, potential syn-depositional contaminants and elemental redistribution during diagenesis. Microbial carbonates, cements and background sediments were analysed for stable iso...

Coprecipitation experiments of Np(V) and U(VI) with calcite were performed in mixed-flow reactors under steady state conditions at room temperature for up to 400 h at precipitation rates of 1.0 × 10-8 to 6.8 × 10-8 mol/(m2 s). The saturation index with respect to calcite varied between 0.04 and 0.95. Initial Np(V) or U(VI) concentrations were 1 μmol/L, 0.01 mol/L NaCl was used as background ele...

Three-phase pwm voltage source inverters are widely employed in high performance ac drive system, active filters and uninterrupted power supply (UPS) etc.For these applications, the converter should provides good dynamic response. However the performance of the converter system largely depends on the accuracy of the applied current control strategy. The current controllers can be classified as ...

BACKGROUND This study provides experimental evidence for biologically induced precipitation of magnesium carbonates, specifically dypingite (Mg5(CO3)4(OH)2.5H2O), by cyanobacteria from an alkaline wetland near Atlin, British Columbia. This wetland is part of a larger hydromagnesite (Mg5(CO3)4(OH)2.4H2O) playa. Abiotic and biotic processes for magnesium carbonate precipitation in this environmen...