Results 1 to 10 of about 2,420 (129)

Highly fractionated chromium isotopes in Mesoproterozoic-aged shales and atmospheric oxygen [PDF]

open access: yesNature Communications, 2018
There is a long standing debate whether low atmospheric oxygen levels during the Mesoproterozoic Era hindered the evolution of crown-group animals. Here, the authors show with shale-hosted chromium isotopes that sufficient atmospheric oxygen for crown ...
Donald E. Canfield   +7 more
doaj   +2 more sources

Precise measurement of chromium isotopes by MC-ICPMS. [PDF]

open access: yesJ Anal At Spectrom, 2014
We report novel analytical procedures allowing for the concurrent determination of the stable and mass-independent Cr isotopic composition of silicate materials by multiple collector inductively coupled mass spectrometry (MC-ICPMS).
Schiller M   +4 more
europepmc   +5 more sources

Method validation and geochemical modelling of chromium speciation in natural waters [PDF]

open access: yesScientific Reports
The study focuses on validating reference methods such as ICP-OES and ICP-MS for detecting ultra-trace levels of chromium in groundwater, where concentrations are typically very low.
Piotr Rusiniak   +3 more
doaj   +2 more sources

Machine learning models for water safety enhancement [PDF]

open access: yesScientific Reports
Humans encounter both natural and artificial radiation sources, including cosmic rays, primordial radionuclides, and radiation generated by human activities.
Fatemeh Ranjbar   +3 more
doaj   +2 more sources

Determination of Trace Elements in Nickel-based High-temperature Alloy by High Resolution Plasma Mass Spectrometry [PDF]

open access: yesZhipu Xuebao, 2023
The nickel content of nickel-based high-temperature alloy is between 50% and 70%, and the alloy contents of chromium, iron, cobalt, molybdenum, aluminum, titanium and tungsten are within 20%.
HU Xuan1   +6 more
doaj   +1 more source

Mechanisms of chromium isotope fractionation and the applications in the environment

open access: yesEcotoxicology and Environmental Safety, 2022
Chromium (Cr) is a toxic heavy metal that gives rise to environmental pollution and human risk. Chromium stable isotopes have a wide range of applications in both environmental field and earth science field.
Ying Li   +5 more
doaj   +1 more source

Summit of the N=40 island of inversion: Precision mass measurements and ab initio calculations of neutron-rich chromium isotopes

open access: yesPhysics Letters B, 2022
Mass measurements continue to provide invaluable information for elucidating nuclear structure and scenarios of astrophysical interest. The transition region between the Z=20 and 28 proton shell closures is particularly interesting due to the onset and ...
R. Silwal   +26 more
doaj   +1 more source

Biogeochemical cycling of chromium and chromium isotopes in the sub-tropical North Atlantic Ocean

open access: yesFrontiers in Marine Science, 2023
Chromium (Cr) is a redox-sensitive element and because Cr isotopes are fractionated by redox and/or biological processes, the Cr isotopic composition of ancient marine sediments may be used to infer changes in past seawater oxygenation or biological ...
Wenhao Wang   +6 more
doaj   +1 more source

Modeling the marine chromium cycle: new constraints on global-scale processes [PDF]

open access: yesBiogeosciences, 2021
Chromium (Cr) and its isotopes hold great promise as a tracer of past oxygenation and marine biological activity due to the contrasted chemical properties of its two main oxidation states, Cr(III) and Cr(VI), and the associated isotope fractionation ...
F. Pöppelmeier   +8 more
doaj   +1 more source

A systematic look at chromium isotopes in modern shells – implications for paleo-environmental reconstructions [PDF]

open access: yesBiogeosciences, 2018
The chromium isotope system (53Cr ∕ 52Cr, expressed as δ53Cr relative to NIST SRM 979) in marine biogenic and non-biogenic carbonates is currently being evaluated as a proxy for the redox state of the ocean.
R. Frei   +4 more
doaj   +1 more source

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