Results 141 to 150 of about 1,212,853 (207)

Geochemistry and Cr stable isotopes of Cr-contaminated groundwater in León valley, Guanajuato, México

Applied Geochemistry, 2012
Abstract Leon valley, located in the Mexican state of Guanajuato, has a long history (35+ a) of Cr contamination of groundwater and surface water. Here data are presented for Cr, major ion and trace element concentrations and Cr stable isotope measurements of groundwater in a heavily contaminated aquifer in Buenavista, where Cr ore processing residue
Alejandro Villalobos-Aragón, Andre S. Ellis, María A. Armienta, Ofelia Morton-Bermea, Thomas M. Johnson   +4 more
openaire   +2 more sources

The coordination of Cr2+ in silicate glasses and implications for mineral-melt fractionation of Cr isotopes

Chemical Geology, 2021
The Cr2+-O and Cr3+-O bond lengths in CaO-MgO-Al2O3-SiO2 glasses containing ~0.3 wt% Cr with Cr2+/ΣCr = ~ 1 or 0 (where ΣCr = Cr2+ + Cr3+) were determined by extended X-ray absorption fine structure (EXAFS) spectroscopy to be 2.034(5) and 1.967(7) A ...
A. Berry, Laura A. Miller, H. O’Neill, G. Foran   +3 more
semanticscholar   +1 more source

Variations of redox conditions in the atmosphere and Yangtze Platform during the Ediacaran-Cambrian transition: Constraints from Cr isotopes and Ce anomalies

, 2020
The Ediacaran-Cambrian transition was characterized by the evolution from Ediacaran soft-body to Cambrian skeletal organisms, and fluctuations of the marine carbon cycle.
Wei Wei, R. Frei, G. Gilleaudeau, Da Li, Guangyi Wei, F. Huang, H. Ling   +6 more
semanticscholar   +1 more source

Chemisorption, diffusion and permeation of hydrogen isotopes in bcc bulk cr and cr(100) surface: First-principles dft simulations

, 2021
Chromium, a transition metal, is one of the important constituents, used widely in steel. It is of paramount importance to study the behavior of hydrogen isotopes with Cr to design a suitable barrier materials for arresting the permeation of H isotopes ...
A. Boda, Sakshi Bajania, S. Ali, K. T. Shenoy, S. Mohan   +4 more
semanticscholar   +1 more source

Equilibrium isotopic fractionation and isotopic exchange kinetics between Cr(III) and Cr(VI)

Geochimica et Cosmochimica Acta, 2015
Abstract We determined the equilibrium isotope fractionation between Cr(III) and Cr(VI), defined as Δ53CrVI-III = δ53Cr(VI) − δ53Cr(III), and the rates of isotopic exchange between the two redox species under different conditions. In high Cr concentration, low-pH experiments we determined the Δ53CrV-III between CrO42− and Cr(H2O)63+ to be 5.2 ± 0.3 ...
Xiangli Wang, Thomas M. Johnson, Andre S. Ellis   +2 more
openaire   +1 more source

Global Cr-isotope distributions in surface seawater and incorporation of Cr isotopes into carbonate shells [PDF]

, 2015
In this study we present the Cr-isotope composition of surface seawater from several locations worldwide. In addition to the samples from the oceans (Atlantic Ocean, Pacific Ocean, Southern Ocean and Artic Ocean) we analysed water samples from areas with a more limited water exchange (Mediterranean Sea, Baltic Sea, Øresund and Kattegat).
Paulukat, Cora Stefanie, Frei, Robert, Vögelin, Andrea Regula, Samankassou, Elias   +3 more
openaire   +1 more source

Isotope shift in Cr I

Physics Letters A, 1967
Abstract In transitions of the type 3 d 5 4 s − 3 d 5 4 p in a difference in field shift of 4.4 × 10 -3 cm -1 was found for the isotope pairs 54, 52 and 52, 50. This result signifies a jump of field shift at the closed neutron shell N = 28.
K. Heilig, D. Wendlandt
openaire   +1 more source

Isotopic Evidence of Cr Partitioning into Earth’s Core

Science, 2011
Chromium isotopes in meteorites reveal Earth’s accretion history.
Frederic, Moynier, Qing-Zhu, Yin, Edwin, Schauble   +2 more
openaire   +2 more sources

Isotopically enriched rolled Cr foils

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995
Abstract Isotopically enriched self-supporting Cr targets in the thickness range of 0.3 to 2 mg/cm 2 were prepared. After reduction of Cr 2 O 3 , the material was further cleaned and solidified by a simple resistance heating technique. The resulting Cr bead can easily be rolled to the minimum desired thickness of 300 μg/cm 2 .
G Manente, D Blunt
openaire   +1 more source

Contamination and source apportionment of metals in urban road dust (Jinan, China) integrating the enrichment factor, receptor models (FA-NNC and PMF), local Moran's index, Pb isotopes and source-oriented health risk.

Science of the Total Environment, 2023
Contamination and source identifications of metals in urban road dust are critical for remediation and health protection. Receptor models are commonly used for metal source identification, whereas the results are usually subjective and not verified by ...
Xiaoyu Wang, E. Liu, Meng-Xia Yan, Shuwei Zheng, Ying Fan, Yingxue Sun, Zijun Li, Jinling Xu   +7 more
semanticscholar   +1 more source