Variation in the terrestrial isotopic composition and atomic weight of argon (IUPAC Technical Report)

2014 ◽  
Vol 86 (9) ◽  
pp. 1421-1432 ◽  
Author(s):  
J.K. Böhlke
Keyword(s):  
Isotopic Composition ◽  
Radioactive Decay ◽  
Isotopic Fractionation ◽  
Atomic Weight ◽  
Chemical Processes ◽  
Published Data ◽  
Nuclear Transformation ◽  
Rock Interaction ◽  
Physical Chemical ◽  
Mass Dependent

AbstractThe isotopic composition and atomic weight of argon (Ar) are variable in terrestrial materials. Those variations are a source of uncertainty in the assignment of standard properties for Ar, but they provide useful information in many areas of science. Variations in the stable isotopic composition and atomic weight of Ar are caused by several different processes, including (1) isotope production from other elements by radioactive decay (radiogenic isotopes) or other nuclear transformations (e.g., nucleogenic isotopes), and (2) isotopic fractionation by physical-chemical processes such as diffusion or phase equilibria. Physical-chemical processes cause correlated mass-dependent variations in the Ar isotope-amount ratios (40Ar/36Ar, 38Ar/36Ar), whereas nuclear transformation processes cause non-mass-dependent variations. While atmospheric Ar can serve as an abundant and homogeneous isotopic reference, deviations from the atmospheric isotopic ratios in other Ar occurrences limit the precision with which a standard atomic weight can be given for Ar. Published data indicate variation of Ar atomic weights in normal terrestrial materials between about 39.7931 and 39.9624. The upper bound of this interval is given by the atomic mass of 40Ar, as some samples contain almost pure radiogenic 40Ar. The lower bound is derived from analyses of pitchblende (uranium mineral) containing large amounts of nucleogenic 36Ar and 38Ar. Within this interval, measurements of different isotope ratios (40Ar/36Ar or 38Ar/36Ar) at various levels of precision are widely used for studies in geochronology, water–rock interaction, atmospheric evolution, and other fields.

scholarly journals Industrially Purified Nd Materials Identified by Distinct Mass-Dependent Isotopic Composition

2021 ◽  
Vol 2 ◽  
Author(s):  
Nina Bothamy ◽  
Albert Galy
Keyword(s):  
Isotopic Composition ◽  
Chromatographic Separation ◽  
Inductively Coupled Plasma ◽  
Permanent Magnets ◽  
New Technologies ◽  
Radioactive Decay ◽  
Isotopic Fractionation ◽  
Mass Dependent ◽  
Mass Dependent Fractionation ◽  
Nd Isotopic Composition

Rare earth elements (REEs) are considered emerging anthropogenic pollutants. Anthropogenic lanthanum, cerium, samarium, and gadolinium alone, or excess of all the REEs have already been reported in the environment. In addition, it is only a matter of time for neodymium (Nd) of anthropogenic origin to be reported disseminated in the environment, given its growing demand for new technologies and its use in permanent magnets of wind turbine. So far, only in a few cases was the addition of anthropogenic Nd detected in soils and sediments by the measurements of REE concentrations. For this reason, we propose to use the Nd isotopic composition to help the distinction of pollution. The isotopic tracing of Nd using variations in the abundance of 143Nd from the radioactive decay of 147Sm (Nd-radiogenic composition) is one option. Here, we expand the Nd isotopic fingerprinting by the investigation of the stable Nd isotopic composition expressed as δxNd, the relative permil (%0) deviation from the isotopic composition of the pure Nd JNdi-1 reference standard. The measurement of δxNd used a MC-ICPMS (multi-collector inductively coupled plasma mass spectrometry) with sample-standard bracketing technique, allowing the determination of precise and accurate Nd isotopic variations. Our results show that Nd-magnets (Neo) and man-made purified Nd materials are not significantly different on average (respectively, δ148Nd of −0.105 ± 0.023 and −0.120 ± 0.141%0). More importantly, they are different from terrestrial rocks (δ148Nd of −0.051 ± 0.031%0). Moreover, the Nd-radiogenic composition of Neo can be highly variable, even when they come from a single supplier. In addition, the study of all Nd stable isotopic compositions demonstrates that irrespective of their natural origin (witnessed by their Nd-radiogenic composition), all Nd from rocks and man-made materials are related by mass-dependent isotopic fractionation laws. We also have defined a parameter, the Δ148−150Nd′, allowing the distinction of thermodynamic isotopic fractionation (the Δ148−150Nd′ is invariant) from kinetic isotopic fractionation (the Δ148−150Nd′ is negatively correlated with the δ148Nd). Such covariation is observed for anthropogenic materials that could be seen as small deficit in 150Nd (around 5 ppm/%0/amu), but too small to be consistent with nuclear field effect. On the other hand, the anthropogenic material defines a covariation in the Δ148−150Nd'–δ148Nd space in full agreement with the theoretical expectation from mass-dependent kinetic isotopic fractionation. The mass-dependent fractionation of Nd by chromatographic separation is also consistent with a kinetic isotopic fractionation. The purification of Nd from other light REEs by industrial processes involves chromatographic separation and, therefore, is likely to produce anthropogenic Nd with low values for δ148Nd associated with high values for Δ148−150Nd′. Both are resolvable with current MC-ICPMS technology and could be useful to trace incoming anthropogenic pollution in the environment. In soils, the combination of low values for δ148Nd with high values for Δ148−150Nd′ is likely to be an unambiguous pollution signal from the degradation in the environment of Neo or other industrial products, especially if this is associated with an Nd-radiogenic composition inconsistent with the surrounding rocks and soils. In contrast, the industrial residue of Nd purification could be characterized by high δ148Nd with low values for Δ148−150Nd′, and the leak or the discharge of such residue could also be unambiguously distinguished.

What CO 2 well gases tell us about the origin of noble gases in the mantle and their relationship to the atmosphere

2008 ◽  
Vol 366 (1883) ◽  
pp. 4183-4203 ◽  
Author(s):  
Chris J Ballentine ◽  
Greg Holland
Keyword(s):  
Solar Wind ◽  
Isotopic Composition ◽  
Solar Nebula ◽  
Noble Gases ◽  
Noble Gas ◽  
Isotopic Fractionation ◽  
Elemental Abundance ◽  
Published Data ◽  
Abundance Pattern ◽  
New Information

Study of commercially produced volcanic CO 2 gas associated with the Colorado Plateau, USA, has revealed substantial new information about the noble gas isotopic composition and elemental abundance pattern of the mantle. Combined with published data from mid-ocean ridge basalts, it is now clear that the convecting mantle has a maximum 20 Ne/ 22 Ne isotopic composition, indistinguishable from that attributed to solar wind-implanted (SWI) neon in meteorites. This is distinct from the higher 20 Ne/ 22 Ne isotopic value expected for solar nebula gases. The non-radiogenic xenon isotopic composition of the well gases shows that 20 per cent of the mantle Xe is ‘solar-like’ in origin, but cannot resolve the small isotopic difference between the trapped meteorite ‘Q’-component and solar Xe. The mantle primordial 20 Ne/ 132 Xe is approximately 1400 and is comparable with the upper end of that observed in meteorites. Previous work using the terrestrial 129 I– 129 Xe mass balance demands that almost 99 per cent of the Xe (and therefore other noble gases) has been lost from the accreting solids and that Pu–I closure age models have shown this to have occurred in the first ca 100 Ma of the Earth's history. The highest concentrations of Q-Xe and solar wind-implanted (SWI)-Ne measured in meteorites allow for this loss and these high-abundance samples have a Ne/Xe ratio range compatible with the ‘recycled-air-corrected’ terrestrial mantle. These observations do not support models in which the terrestrial mantle acquired its volatiles from the primary capture of solar nebula gases and, in turn, strongly suggest that the primary terrestrial atmosphere, before isotopic fractionation, is most probably derived from degassed trapped volatiles in accreting material. By contrast, the non-radiogenic argon, krypton and 80 per cent of the xenon in the convecting mantle have the same isotopic composition and elemental abundance pattern as that found in seawater with a small sedimentary Kr and Xe admix. These mantle heavy noble gases are dominated by recycling of air dissolved in seawater back into the mantle. Numerical simulations suggest that plumes sampling the core–mantle boundary would be enriched in seawater-derived noble gases compared with the convecting mantle, and therefore have substantially lower 40 Ar/ 36 Ar. This is compatible with observation. The subduction process is not a complete barrier to volatile return to the mantle.

scholarly journals Variation of lead isotopic composition and atomic weight in terrestrial materials (IUPAC Technical Report)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiang-Kun Zhu ◽  
Jacqueline Benefield ◽  
Tyler B. Coplen ◽  
Zhaofu Gao ◽  
Norman E. Holden
Keyword(s):  
Isotopic Composition ◽  
Radioactive Decay ◽  
Isotope Ratios ◽  
Atomic Weight ◽  
High Grade ◽  
A Value ◽  
Metamorphic Terrain ◽  
Phosphate Mineral ◽  
Technical Report ◽  
North Western

AbstractThe isotopic composition and atomic weight of lead are variable in terrestrial materials because its three heaviest stable isotopes are stable end-products of the radioactive decay of uranium (238U to 206Pb; 235U to 207Pb) and thorium (232Th to 208Pb). The lightest stable isotope, 204Pb, is primordial. These variations in isotope ratios and atomic weights provide useful information in many areas of science, including geochronology, archaeology, environmental studies, and forensic science. While elemental lead can serve as an abundant and homogeneous isotopic reference, deviations from the isotope ratios in other lead occurrences limit the accuracy with which a standard atomic weight can be given for lead. In a comprehensive review of several hundred publications and analyses of more than 8000 samples, published isotope data indicate that the lowest reported lead atomic weight of a normal terrestrial materials is 206.1462 ± 0.0028 (k = 2), determined for a growth of the phosphate mineral monazite around a garnet relic from an Archean high-grade metamorphic terrain in north-western Scotland, which contains mostly 206Pb and almost no 204Pb. The highest published lead atomic weight is 207.9351 ± 0.0005 (k = 2) for monazite from a micro-inclusion in a garnet relic, also from a high-grade metamorphic terrain in north-western Scotland, which contains almost pure radiogenic 208Pb. When expressed as an interval, the lead atomic weight is [206.14, 207.94]. It is proposed that a value of 207.2 be adopted for the single lead atomic-weight value for education, commerce, and industry, corresponding to previously published conventional atomic-weight values.

scholarly journals Hybrid Manufacturing based on the combination of Mechanical and Electro Physical–Chemical Processes

Procedia CIRP ◽  
2020 ◽  
Vol 95 ◽  
pp. 649-661
Author(s):  
Bert Lauwers ◽  
Nataliia Chernovol ◽  
Benjamin Peeters ◽  
Dries Van Camp ◽  
Thomas Van Riel ◽  
...  
Keyword(s):  
Chemical Processes ◽  
Hybrid Manufacturing ◽  
Physical Chemical

scholarly journals INVESTIGATION OF SOLID PARTICLES UNDER THE ACTION OF AN ACOUSTIC FIELD / SKYSTYJE ESANČIŲ KIETŲJŲ DALELIŲ SĄVEIKOS AKUSTINIAME LAUKE TYRIMAS

2013 ◽  
Vol 5 (6) ◽  
pp. 655-658
Author(s):  
Egidijus Mykolaitis ◽  
Andrius Styra ◽  
Vladas Vekteris
Keyword(s):  
Water Treatment ◽  
Ground Water ◽  
Acoustic Field ◽  
Chemical Industry ◽  
Iron Concentration ◽  
Chemical Processes ◽  
Solid Particles ◽  
Common Elements ◽  
Physical Chemical

Iron is one of the most common elements in ground water. Bythe HN 24:2003 iron concentration in water can‘t be higher than200 μg/l. Water treatment with an acoustic field is a very relevanttopic. Acoustic field is widely used in industrion, medicine,chemical industry and manufacturing. When water is affectedby ultrasound, physical-chemical processes begin. Ultrasoundvibrations lead to dispersion, degasation and coagulation. Ironparticles connect to each other when distance between them istwo times bigger then their own radius. R = 2R. And if thisprocess continues particles connect one by one. In this article teststand and methodics using ultrasonic piezoceramic are shown. Santrauka Geležis – dažniausiai požeminiuose vandenyse aptinkama priemaiša, kuri prastina geriamojo vandens savybes, todėl būtina bendrosios geležies koncentraciją sumažinti iki 0,2 mg/l. Vienas iš geležies šalinimo būdu yra paremtas ultragarso panaudojimu. Straipsnyje glaustai aptarti bendrosios geležies būviai vandenyje, jos šalinimo metodai ir pateikta eksperimentinė metodika. Eksperimentas atliktas naudojant skirtingų dažnių garso bangas nuo 8 kHz iki 20 kHz diapazone. Akustinio lauko daromai įtakai nustatyti, naudojant skirtingų dažnių garso bangas, buvo panaudoti trys skirtingi vandens debitai. Iš gautų rezultatų suformuluotos išvados.

Use of Wood Biomass in Slovakia

2014 ◽  
Vol 1001 ◽  
pp. 126-130
Author(s):  
Tomáš Bakalár ◽  
Henrieta Pavolová ◽  
Milan Búgel ◽  
Ľubica Kozáková
Keyword(s):  
Energy Source ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
Organic Material ◽  
Chemical Processes ◽  
Wood Chips ◽  
Wood Biomass ◽  
Biochemical Processes ◽  
Physical Chemical ◽  
Thermochemical Processes

Biomass is organic material, the second most important source of energy. Biomass is a renewable energy source. Wood biomass is used as source of energy for heating in many regions in Slovakia. It is because of its availability. Wood biomass is an easily accessible and affordable source of energy. At present, thermochemical processes, biochemical processes and physical-chemical processes are used for biomass utilization. In the article a suitable technology for combustion of wood chips is proposed. It consists of five main technological parts: transport of wood chips, silo, combustion boiler, and stack.

scholarly journals Seasonal changes in the D  /  H ratio of fatty acids of pelagic microorganisms in the coastal North Sea

2016 ◽  
Vol 13 (19) ◽  
pp. 5527-5539 ◽  
Author(s):  
Sandra Mariam Heinzelmann ◽  
Nicole Jane Bale ◽  
Laura Villanueva ◽  
Danielle Sinke-Schoen ◽  
Catharina Johanna Maria Philippart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Isotopic Composition ◽  
North Sea ◽  
Phytoplankton Bloom ◽  
Isotopic Fractionation ◽  
Spring Phytoplankton Bloom ◽  
Fractionation Factor ◽  
Culture Studies ◽  
Hydrogen Isotopic Composition

Abstract. Culture studies of microorganisms have shown that the hydrogen isotopic composition of fatty acids depends on their metabolism, but there are only few environmental studies available to confirm this observation. Here we studied the seasonal variability of the deuterium-to-hydrogen (D / H) ratio of fatty acids in the coastal Dutch North Sea and compared this with the diversity of the phyto- and bacterioplankton. Over the year, the stable hydrogen isotopic fractionation factor ε between fatty acids and water (εlipid/water) ranged between −172 and −237 ‰, the algal-derived polyunsaturated fatty acid nC20:5 generally being the most D-depleted (−177 to −235 ‰) and nC18:0 the least D-depleted fatty acid (−172 to −210 ‰). The in general highly D-depleted nC20:5 is in agreement with culture studies, which indicates that photoautotrophic microorganisms produce fatty acids which are significantly depleted in D relative to water. The εlipid/water of all fatty acids showed a transient shift towards increased fractionation during the spring phytoplankton bloom, indicated by increasing chlorophyll a concentrations and relative abundance of the nC20:5 polyunsaturated fatty acids, suggesting increased contributions of photoautotrophy. Time periods with decreased fractionation (less negative εlipid/water values) can potentially be explained by an increased contribution of heterotrophy to the fatty acid pool. Our results show that the hydrogen isotopic composition of fatty acids is a promising tool to assess the community metabolism of coastal plankton potentially in combination with the isotopic analysis of more specific biomarker lipids.

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