• isotopic
  • The isotopic composition of xenon in the Archean atmosphere has evolved through time by mass-dependent fractionation from a precursor comprising cometary and solar/chondritic contributions (referred to as U-Xe). (sciencemag.org)
  • Xe trapped in barite and in fluid inclusions in hydrothermal quartz of Archean ages present Xe isotopic ratios intermediate between modern atmospheric Xe and planetary precursors, showing that atmospheric evolution as a result of mass-dependent fractionation (MDF) was a protracted process still ongoing during the Archean eon [see the study of Avice et al . (sciencemag.org)
  • Understanding isotopic fingerprints and the sources of fractionation that lead to variation between them can be applied to address a diverse array of questions ranging from ecology and hydrology to geochemistry and paleoclimate reconstructions. (wikipedia.org)
  • Most isotopic fractionations (including typical kinetic fractionations and equilibrium fractionations) are caused by the effects of the mass of an isotope on atomic or molecular velocities, diffusivities or bond strengths. (wikipedia.org)
  • toxic
  • The access to clean, safe drinking water is seen as a fundamental human right and yet industrial-scale human activities in catchments can pollute water systems with toxic products/chemicals and compromise water quality and quantity, as well as adversely affect the ecosystems of catchments. (sourcewatch.org)
  • Method
  • A method combining liquid/liquid extraction and chromatographic fractionation has been developed for the preparation of pure monophenyltin (MPhT), diphenyltin (DPhT), and triphenyltin (TPhT), synthesized from isotope-enriched Sn metal using phenylation of SnI(4) in diethylether (DEE) followed by quenching with HBr and water. (diva-portal.org)
  • affinity
  • The chemical behavior of an atom - its affinity for other elements and the type of bonds it forms - is determined by the arrangement of electrons in orbitals, particularly the outermost (valence) electrons. (wikipedia.org)
  • methods
  • Tsvet applied his observations with filter paper extraction to the new methods of column fractionation that had been developed in the 1890s for separating the components of petroleum. (wikipedia.org)
  • mass
  • HYSYS is able to perform many of the core calculations of chemical engineering, including those concerned with mass balance, energy balance, vapor-liquid equilibrium, heat transfer, mass transfer, chemical kinetics, fractionation, and pressure drop. (wikipedia.org)
  • Mass-independent fractionation also has been observed in ozone. (wikipedia.org)
  • Mass-independent fractionation of sulfur can be observed in ancient sediments, where it preserves a signal of the prevailing environmental conditions. (wikipedia.org)
  • The disappearance of distinctive non-mass-dependent (NMD) sulphur isotope fractionations in sedimentary rocks deposited after about 2.4-2.3 Gyr ago16 (Fig. 2). (wikipedia.org)
  • Soil
  • A large number of SOM fractionation procedures have been developed to distinguish between SOM to study whether it is liable or recalcitrant to activities of soil microbes. (oalib.com)
  • oxygen
  • To lower energy consumption at a sewage treatment plant (STP), primary settling could be enhanced to direct more chemical oxygen demand (COD) to anaerobic digestion (AD) for increased biogas production and decreased aeration. (environmental-expert.com)
  • common
  • However, for the rest of the century the more common term was "chemical geology", and there was little contact between geologists and chemists. (wikipedia.org)