Computer modelling techniques have been employed to qualitatively and quantitatively investigate the uptake and distribution of carbonate groups in the hydroxyapatite lattice. Two substitutional defects are considered: the type-A defect, where the carbonate group is located in the hydroxy channel, and the type-B defect, where the carbonate group is located at the position of a phosphate group. ...

Studies of the dC of pore water dissolved inorganic carbon (dC-DIC) were carried out in shallow water carbonate sediments of the Great Bahamas Bank (GBB) to further examine sediment–seagrass relationships and to more quantitatively describe the couplings between organic matter remineralization and sediment carbonate diagenesis. At all sites studied dC-DIC provided evidence for the dissolution o...

Measurements of electrochemical (EC) arsenite oxidation demonstrated thatthe arsenite oxidation current increased in the presence of carbonate while the potential of the onset of EC arsenite oxidation exhibited a strong shift toward less positive values. Examination of pH and total carbonate concentration effects on the EC arsenite oxidation parameters showed that they were affected solely by t...

Increasing atmospheric carbon dioxide (CO2) through human activities and invasion of anthropogenic CO2 into the surface ocean alters the seawater carbonate chemistry, increasing CO2 and bicarbonate (HCO − 3 ) at the expense of carbonate ion (CO 3 ) concentrations. This redistribution in the dissolved inorganic carbon (DIC) pool decreases pH and carbonate saturation state (). Several components...

The cycling performance and SEI composition of Si nano-particle anodes in electrolytes containing 5–25 wt% fluoroethyelene carbonate (FEC) and 3–6 wt% vinylene carbonate (VC) has been investigated by a combination of by electrochemical cycling, electrochemical impedance spectroscopy, IR-ATR and XPS. The incorporation of FEC or VC changes the cycling performance, impedance, electrode morphology,...

Powders of sodium-carbonate co-substituted hydroxyapatite, having sodium content in the range of 0.25–1.5 wt.% with a 0.25 wt.% step, were prepared by a precipitation-solid state reaction route. Compacts of the powders were sintered in a CO2 flow (4 mL/min) at 1100 °C for 2 h. The sintered ceramics contained sodium and carbonate ions in the ranges of 0–1.5 wt.% and 1.3–6 wt.%, respectively, whi...

Carbonate anion exchange reactions with water in the uranyl-carbonate and calcium-uranyl-carbonate aqueous systems have been investigated using computational methods. Classical molecular dynamics (MD) simulations with the umbrella sampling technique were employed to determine potentials of mean force for the exchange reactions of water and carbonate. The presence of calcium counter-ions is pred...

In this study, the non-catalytic supercritical method has been studied in utilizing dimethyl carbonate. It was demonstrated that, the supercritical dimethyl carbonate process without any catalysts applied, converted triglycerides to fatty acid methyl esters with glycerol carbonate and citramalic acid as by-products, while free fatty acids were converted to fatty acid methyl esters with glyoxal....

Located in northern Peru, at the lowest segment of Central Andes, Bagua Basin contains a Campanian to Pleistocene sedimentary record that archives local paleoenvironmental and tectonic history. We present new ?18O ?13C signatures pedogenic carbonate nodules from paleosols Campanian–Maastrichtian Fundo El Triunfo Formation upper Eocene–middle Miocene Sambimera reconstruct isotopic composition pa...